Surgical instruments with flexible ball chain drive arrangements

ABSTRACT

Surgical instruments that comprise an axially movable firing member that is configured to be driven between a starting position and an ending position within a surgical end effector of the surgical instrument by an upper an upper chain-drive assembly and a lower chain-drive assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 63/057,430,entitled SURGICAL INSTRUMENTS WITH TORSION SPINE DRIVE ARRANGEMENTS,filed Jul. 28, 2020, of U.S. Provisional Patent Application Ser. No.63/057,432, entitled ARTICULATION JOINT ARRANGEMENTS FOR SURGICALINSTRUMENTS, filed Jul. 28, 2020, the disclosures of which areincorporated by reference herein in their entireties.

BACKGROUND

The present invention relates to surgical instruments and, in variousarrangements, to surgical stapling and cutting instruments and staplecartridges for use therewith that are designed to staple and cut tissue.The surgical instruments may be configured for use in open surgicalprocedures, but have applications in other types of surgery, such aslaparoscopic, endoscopic, and robotic-assisted procedures and mayinclude end effectors that are articulatable relative to a shaft portionof the instrument to facilitate precise positioning within a patient.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the various aspects are set forth withparticularity in the appended claims. The described aspects, however,both as to organization and methods of operation, may be best understoodby reference to the following description, taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a perspective view of a surgical end effector portion of asurgical instrument in accordance with at least one aspect of thepresent disclosure;

FIG. 2 is a side view of the surgical end effector portion instrument ofFIG. 1 in a closed orientation;

FIG. 3 is an end view of the surgical end effector of FIG. 2 ;

FIG. 4 is a top view of the surgical end effector of FIG. 2 ;

FIG. 5 is an exploded assembly view of a portion of the surgicalinstrument of FIG. 1 ;

FIG. 6 is an exploded assembly view of an elongate shaft assembly of thesurgical instrument of FIG. 1 ;

FIG. 7 is another exploded assembly view of the elongate shaft assemblyof FIG. 6 ;

FIG. 8 is an exploded assembly view of a firing system and a rotarydrive system according to at least one aspect of the present disclosure;

FIG. 9 is a side view of a firing member and upper and lower flexiblespine assemblies of the firing system in engagement with a rotary drivescrew of the rotary drive system of FIG. 8 ;

FIG. 10 is a cross-sectional view of the firing member and upper andlower flexible spine assemblies of FIG. 9 ;

FIG. 11 is a side elevational view of the firing member and upper andlower flexible spine assemblies in engagement with the rotary drivescrew of FIG. 9 ;

FIG. 12 is a cross-sectional end view of the surgical end effector ofFIG. 4 taken along line 12-12 in FIG. 4 ;

FIG. 13 is an exploded perspective view of two adjacent upper vertebramembers of the upper flexible spine assembly of FIG. 10 ;

FIG. 14 is an exploded perspective view of two adjacent lower vertebramembers of the lower flexible spine assembly of FIG. 10 ;

FIG. 15 is a top view of a firing member and upper and lower flexiblespine assemblies in engagement with the rotary drive screw of FIG. 9 ;

FIG. 16 is a perspective view of a CV drive shaft assembly of the rotarydrive system of FIG. 8 in an articulated orientation;

FIG. 17 is a perspective view of the firing system of FIG. 8 in drivingengagement with the CV drive shaft assembly of FIG. 16 in accordancewith at least one aspect of the present disclosure;

FIG. 18 is a perspective view of a drive joint of the CV drive shaftassembly of FIG. 16 ;

FIG. 19 is a cross-sectional view of a portion of the surgicalinstrument of FIG. 4 taken along line 19-19 in FIG. 4 ;

FIG. 20 is a partial perspective view of a proximal end portion of thesurgical end effector and portions of the firing system and the rotarydrive system of the surgical instrument of FIG. 1 ;

FIG. 21 is a perspective view of the rotary drive system of the surgicalinstrument of FIG. 1 in driving engagement with the firing systemthereof in accordance with at least one aspect of the presentdisclosure;

FIG. 22 is an exploded perspective view of the rotary drive screw andthrust bearing arrangement of the firing system of FIG. 21 ;

FIG. 23 is a side view of the rotary drive screw of FIG. 22 ;

FIG. 24 is a partial cross-sectional side view of a portion of the lowerflexible spine assembly and a portion of the firing member of FIG. 21 indriving engagement with a portion of the rotary drive screw;

FIG. 25 is a perspective view of the firing member in a home or startingposition within the surgical end effector of the surgical instrument ofFIG. 1 ;

FIG. 26 is a side view illustrating the upper flexible spine assemblyand the lower flexible spine assembly of FIG. 21 in driving engagementwith the rotary drive screw after the firing member has been drivendistally from a home or starting position;

FIG. 27 is a partial cross-sectional perspective view of a portion ofthe surgical end effector, firing system and rotary drive system of thesurgical instrument of FIG. 1 according to at least one aspect of thepresent disclosure with an outer elastomeric joint assembly of anarticulation joint omitted for clarity;

FIG. 28 is another partial perspective view of a portion of the surgicalend effector, firing system and rotary drive system of FIG. 27 with anouter elastomeric joint assembly of an articulation joint and portionsof the elongate shaft assembly omitted for clarity;

FIG. 29 is a top view of the surgical end effector of FIG. 27articulated in a first direction relative to a portion of the elongateshaft assembly in accordance with at least one aspect of the presentdisclosure;

FIG. 30 is a side view of the surgical end effector of FIG. 29articulated in another direction relative to a portion of the elongateshaft assembly in accordance with at least one aspect of the presentdisclosure;

FIG. 31 is a perspective view of the surgical end effector of FIG. 29articulated in multiple planes with respect to a portion of the elongateshaft assembly in accordance with at least one aspect of the presentdisclosure;

FIG. 32 is a side elevational view of a portion of another surgicalinstrument that employs another outer elastomeric joint assembly inaccordance with at least one aspect of the present disclosure;

FIG. 33 is a partial cross-sectional perspective view of the surgicalinstrument of FIG. 32 ;

FIG. 34 is a perspective view of a portion of the outer elastomericjoint assembly of FIG. 32 ;

FIG. 35 is a cross-sectional end view of a portion of the surgicalinstrument of FIG. 19 taken along lines 35-35 in FIG. 19 ;

FIG. 36 is a cross-sectional end view of a portion of the surgicalinstrument of FIG. 19 taken along lines 36-36 in FIG. 19 ;

FIG. 37 is a partial cross-sectional view of a portion of an anvil capand an upper vertebra member of the surgical instrument of FIG. 19 inaccordance with at least one aspect of the present disclosure;

FIG. 38 is a side view of a portion of the surgical end effector of thesurgical instrument of FIG. 19 with an anvil thereof in an open positionin accordance with at least one aspect of the present disclosure andwith portions of the surgical end effector omitted for clarity;

FIG. 39 is a partial cross-sectional side view of the surgical endeffector of FIG. 38 with the anvil in an open position and the firingmember in the home or starting position in accordance with at least oneaspect of the present disclosure;

FIG. 40 is another partial cross-sectional side view of the surgical endeffector of FIG. 39 with the anvil in a partially closed position;

FIG. 41 is another partial cross-sectional side view of the surgical endeffector of FIG. 39 with the anvil in a fully closed position and thefiring member distally advancing through the surgical end effector;

FIG. 42 is a partial side elevational view of the surgical end effectorof FIG. 19 with portions thereof omitted for clarity to illustrate theanvil opening springs applying an opening motion to the anvil and withthe firing member in a home or starting position;

FIG. 43 is another partial side view of the surgical end effector ofFIG. 42 , after the firing member has moved proximally a short distanceto apply a quick closure motion to the anvil for grasping purposes;

FIG. 44 is a cross-sectional view of the surgical end effector of FIG.19 with the jaws thereof in a closed position and the firing memberthereof in a proximal-most position;

FIG. 45 is another cross-sectional view of the surgical end effector ofFIG. 44 , after the firing member has been distally advanced to theending position within the surgical end effector;

FIG. 46 is a perspective view of a portion of another surgicalinstrument;

FIG. 47 is a side elevational view of a surgical end effector of thesurgical instrument of FIG. 46 , with the jaws thereof in an openposition;

FIG. 48 is another side view of the surgical end effector of FIG. 48with the jaws thereof in a closed position;

FIG. 49 is an exploded assembly view of a portion of the surgicalinstrument of FIG. 46 ;

FIG. 50 is a perspective view of a firing member and portions of anupper flexible spine assembly and a lower flexible spine assembly of afiring system of the surgical instrument of FIG. 46 ;

FIG. 51 is a cross-sectional side view of the portions of the firingsystem depicted in FIG. 50 ;

FIG. 52 is a partial exploded assembly view of the upper flexible spineassembly and lower flexible spine assembly depicted in FIG. 51 ;

FIG. 53 is a partial cross-sectional end view of an upper portion of thefiring member depicted in FIG. 50 ;

FIG. 54 is a cross-sectional end view of the surgical end effector ofthe surgical instrument of FIG. 46 , with the jaws thereof in a closedposition;

FIG. 55 is a view of a proximal face of an annular rib member of amovable exoskeleton assembly of the surgical instrument of FIG. 46 ;

FIG. 56 is a view of a distal face of the annular rib member of FIG. 55;

FIG. 57 is a side view of the annular rib member of FIGS. 55 and 56 ;

FIG. 58 is a partial cross-sectional view of a portion of the surgicalinstrument of FIG. 46 ;

FIG. 59 is a side view of an articulation joint of the surgicalinstrument of FIG. 46 when the surgical end effector thereof is in anunarticulated position;

FIG. 60 is another side view of the articulation joint of FIG. 59 whenthe surgical end effector is in an articulated position;

FIG. 61 is partial perspective view of a portion of the surgicalinstrument of FIG. 46 with the surgical end effector omitted forclarity;

FIG. 62 is another partial perspective view of a portion of the surgicalinstrument of FIG. 46 ;

FIG. 63 is another partial perspective view of a portion of the surgicalinstrument of FIG. 46 ;

FIG. 64 is a perspective view of a CV drive shaft assembly and a portionof the elongate shaft assembly of the surgical instrument of FIG. 46 ;

FIG. 65 is another perspective view of the CV drive shaft assembly andelongated shaft assembly of FIG. 64 with a drive cover embodimentinstalled around the CV drive shaft assembly;

FIG. 66 is another perspective view of the CV drive shaft assembly andelongated shaft assembly of FIG. 64 with another drive cover embodimentinstalled around the CV drive shaft assembly;

FIG. 67 is another perspective view of the CV drive shaft assembly andelongated shaft assembly of FIG. 64 with another drive cover embodimentinstalled around the CV drive shaft assembly;

FIG. 68 is a side view of a portion of the firing system of the surgicalinstrument of FIG. 46 with the drive cover of FIG. 67 installed aroundthe CV drive shaft assembly;

FIG. 69 is another side view of the portion of the firing system anddrive cover of FIG. 68 ;

FIG. 70 is a cross-sectional view of a portion of another surgicalinstrument;

FIG. 71 is a cross-sectional end view of a surgical end effector of thesurgical instrument of FIG. 70 ;

FIG. 72 is a cross-sectional side view of a rotary drive nut inengagement with drive components of the surgical instrument of FIG. 70 ;

FIG. 73 is a partial side view of a surgical end effector of anothersurgical instrument that employs a series of flexibly linked drivecomponents to drive a firing member through the surgical end effector;

FIG. 74 is a side view of a portion of the series of flexibly linkeddrive components of the surgical instrument of FIG. 73 prior toengagement with a rotary drive gear in the surgical end effector;

FIG. 75 is another side view of the portion of drive components of FIG.74 after being engaged with the rotary drive gear to form a rigid seriesof drive components;

FIG. 76 is a partial cross-sectional view of the rotary drive system ofthe surgical instrument of FIG. 74 with components in the series offlexible drive components in driving engagement with the rotary drivegear thereof;

FIG. 77 is a side view of a portion of rotary firing system and firingmember of another surgical instrument;

FIG. 78 is a side view of a portion of a rotary firing system and firingmember of another surgical instrument;

FIG. 79 is a side view of a portion of a rotary firing system and firingmember of another surgical instrument;

FIG. 80 is a partial view of another surgical instrument that employs arotary driven firing system to drive a firing member through a surgicalend effector with an anvil of the surgical end effector in an openposition;

FIG. 81 is another partial side view of the surgical instrument and endeffector of FIG. 80 with the anvil thereof in a closed position;

FIG. 82 is a perspective view of portions of the rotary driven firingsystem of the surgical instrument of FIG. 80 ;

FIG. 83 is a top view of a portion of the rotary driven firing systemdepicted in FIG. 82 ;

FIG. 84 is a perspective view of a guide member and rotary drive shaftof the rotary driven firing system of FIG. 83 ;

FIG. 85 is a perspective view of a portion of another flexible firingdrive assembly that may be employed with the firing drive system of FIG.83 ;

FIG. 86 is another perspective view of a portion of another flexiblefiring drive assembly embodiment that may be employed with the firingdrive system of FIG. 83 ;

FIG. 87 is a perspective view of a surgical end effector of anothersurgical instrument with an anvil thereof in an open position and thesurgical end effector in an unarticulated orientation;

FIG. 88 is an exploded assembly view of the surgical end effector andsurgical instrument of FIG. 87 ;

FIG. 89 is a side elevational view of an articulation joint of thesurgical instrument of FIG. 87 ;

FIG. 90 is a top view of the articulation joint of FIG. 89 ;

FIG. 91 is a perspective view of the articulation joint of FIG. 89 and acable-controlled closure pulley system for applying closing motions tothe anvil of the surgical end effector of FIG. 89 ;

FIG. 92 is a perspective view of a portion of the surgical end effectorof FIG. 89 articulated by the articulation joint of FIG. 89 ;

FIG. 93 is another perspective view of the cable-controlled closurepulley system of FIG. 91 ;

FIG. 94 is an end view of a pulley unit of the cable-controlled pulleysystem of FIG. 93 ;

FIG. 95 is a side elevational view of a first lateral alpha wrap pulleyof the pulley unit of FIG. 94 ;

FIG. 96 is a side cross-sectional view of a portion of the surgical endeffector of FIG. 89 with the anvil of the surgical end effector in anopen position;

FIG. 97 is another side elevational view of the surgical end effector ofFIG. 96 with the anvil in a closed position;

FIG. 98 is a perspective view of the articulation joint andcable-controlled closure system of the surgical instrument of FIG. 87with a central joint member and a distal joint member articulatedrelative to a proximal joint member of the articulation joint;

FIG. 99 is another perspective view of the articulation joint andcable-controlled closure system of the surgical instrument of FIG. 87with the distal joint member articulated through a second articulationplane relative to a central joint member of the articulation joint;

FIG. 100 is a side elevational view of portions of a firing drive systemof the surgical instrument of FIG. 87 ;

FIG. 101 is another perspective view of the firing drive system of FIG.100 with upper chain link features and lower chain link features inarticulated positions;

FIG. 102 is another side view of the firing drive system of FIG. 100with the upper chain link features and lower chain link features indriving engagement with a rotary drive screw of the firing drive system;

FIG. 103 is a cross-sectional end view of the surgical end effector ofFIG. 87 with the anvil thereof in a closed position;

FIG. 104 is a cross-sectional side view of a portion of the surgicalinstrument of FIG. 87 with the firing member in a starting position andthe anvil in a closed position;

FIG. 105 is an exploded assembly view of a rotary drive system of thesurgical instrument of FIG. 87 ;

FIG. 106 is a perspective view of a first drive shaft segment and asecond drive shaft segment of the rotary drive system of FIG. 105 ;

FIG. 107 is a perspective view of the surgical end effector of FIG. 87with the rotary drive system in an articulated orientation;

FIG. 108 is an exploded assembly view of an articulation joint and aportion of the rotary drive system of the surgical instrument of FIG. 87;

FIG. 109 is a cross-sectional view of the articulation joint and rotarydrive system of FIG. 108 in an unarticulated orientation;

FIG. 110 is another cross-sectional view of the articulation joint androtary drive system of FIG. 109 with a proximal joint member of thearticulation joint articulated relative to a central joint member of thearticulation joint;

FIG. 111 is a partial side elevational view of the surgical instrumentof FIG. 87 illustrating one form of a cable tensioning system with thesurgical end effector in an unarticulated orientation;

FIG. 112 is another partial side view of the surgical instrument andcable tensioning system of FIG. 111 with the surgical end effector in anarticulated orientation;

FIG. 113 is a partial side elevational view of the surgical instrumentof FIG. 87 illustrating another form of a cable tensioning system withthe surgical end effector in an unarticulated orientation; and

FIG. 114 is another partial side view of the surgical instrument andcable tensioning system of FIG. 113 with the surgical end effector in anarticulated orientation.

DETAILED DESCRIPTION

Applicant of the present application owns the following U.S. PatentApplications that were filed on Jun. 28, 2021 and which are each hereinincorporated by reference in their respective entireties:

-   -   U.S. patent application Ser. No. 17/360,133, entitled SURGICAL        INSTRUMENTS WITH TORSION SPINE DRIVE ARRANGEMENTS, now U.S.        Patent Application Publication No. 2022-0031313;    -   U.S. patent application Ser. No. 17/360,139, entitled SURGICAL        INSTRUMENTS WITH FIRING MEMBER CLOSURE FEATURES, now U.S. Patent        Application Publication No. 2022-0031322;    -   U.S. patent application Ser. No. 17/360,149, entitled SURGICAL        INSTRUMENTS WITH SEGMENTED FLEXIBLE DRIVE ARRANGEMENTS, now U.S.        Patent Application Publication No. 2022-0031314;    -   U.S. patent application Ser. No. 17/360,176, entitled SURGICAL        INSTRUMENTS WITH DOUBLE SPHERICAL ARTICULATION JOINTS WITH        PIVOTABLE LINKS, now U.S. Patent Application Publication No.        2022-0031345;    -   U.S. patent application Ser. No. 17/360,192 entitled SURGICAL        INSTRUMENTS WITH DOUBLE PIVOT ARTICULATION JOINT ARRANGEMENTS,        now U.S. Patent Application Publication No. 2022-0031350;    -   U.S. patent application Ser. No. 17/360,197, entitled SURGICAL        INSTRUMENTS WITH COMBINATION FUNCTION ARTICULATION JOINT        ARRANGEMENTS, now U.S. Patent Application Publication No.        2022-0031323;    -   U.S. patent application Ser. No. 17/360,199, entitled METHOD OF        OPERATING A SURGICAL INSTRUMENT, now U.S. Patent Application        Publication No. 2022-0031315;    -   U.S. patent application Ser. No. 17/360,211, entitled SURGICAL        INSTRUMENTS WITH DUAL SPHERICAL ARTICULATION JOINT ARRANGEMENTS,        now U.S. Patent Application Publication No. 2022-0031324;    -   U.S. patent application Ser. No. 17/360,220, entitled SURGICAL        INSTRUMENTS WITH FLEXIBLE FIRING MEMBER ACTUATOR CONSTRAINT        ARRANGEMENTS, now U.S. Patent Application Publication No.        2022-0031320;    -   U.S. patent application Ser. No. 17/360,244, entitled        ARTICULATABLE SURGICAL INSTRUMENTS WITH ARTICULATION JOINTS        COMPRISING FLEXIBLE EXOSKELETON ARRANGEMENTS, now U.S. Patent        Application Publication No. 2022-0031346; and    -   U.S. patent application Ser. No. 17/360,249, entitled SURGICAL        INSTRUMENTS WITH DIFFERENTIAL ARTICULATION JOINT ARRANGEMENTS        FOR ACCOMMODATING FLEXIBLE ACTUATORS, now U.S. Patent        Application Publication No. 2022-0031351.

Numerous specific details are set forth to provide a thoroughunderstanding of the overall structure, function, manufacture, and useof the embodiments as described in the specification and illustrated inthe accompanying drawings. Well-known operations, components, andelements have not been described in detail so as not to obscure theembodiments described in the specification. The reader will understandthat the embodiments described and illustrated herein are non-limitingexamples, and thus it can be appreciated that the specific structuraland functional details disclosed herein may be representative andillustrative. Variations and changes thereto may be made withoutdeparting from the scope of the claims.

The terms “comprise” (and any form of comprise, such as “comprises” and“comprising”), “have” (and any form of have, such as “has” and“having”), “include” (and any form of include, such as “includes” and“including”) and “contain” (and any form of contain, such as “contains”and “containing”) are open-ended linking verbs. As a result, a surgicalsystem, device, or apparatus that “comprises,” “has,” “includes” or“contains” one or more elements possesses those one or more elements,but is not limited to possessing only those one or more elements.Likewise, an element of a system, device, or apparatus that “comprises,”“has,” “includes” or “contains” one or more features possesses those oneor more features, but is not limited to possessing only those one ormore features.

The terms “proximal” and “distal” are used herein with reference to aclinician manipulating the handle portion of the surgical instrument.The term “proximal” refers to the portion closest to the clinician andthe term “distal” refers to the portion located away from the clinician.It will be further appreciated that, for convenience and clarity,spatial terms such as “vertical”, “horizontal”, “up”, and “down” may beused herein with respect to the drawings. However, surgical instrumentsare used in many orientations and positions, and these terms are notintended to be limiting and/or absolute.

References to items in the singular should be understood to includeitems in the plural, and vice versa, unless explicitly stated otherwiseor clear from the text. Grammatical conjunctions are intended to expressany and all disjunctive and conjunctive combinations of conjoinedclauses, sentences, words, and the like, unless otherwise stated orclear from the context. Thus, the term “or” should generally beunderstood to mean “and/or”, etc.

Recitation of ranges of values herein are not intended to be limiting,referring instead individually to any and all values falling within therange, unless otherwise indicated herein, and each separate value withinsuch a range is incorporated into the disclosure as if it wereindividually recited herein. The words “about,” “approximately” or thelike, when accompanying a numerical value, are to be construed asindicating a deviation as would be appreciated by one of ordinary skillin the art to operate satisfactorily for an intended purpose. Similarly,words of approximation such as “approximately” or “substantially” whenused in reference to physical characteristics, should be construed tocontemplate a range of deviations that would be appreciated by one ofordinary skill in the art to operate satisfactorily for a correspondinguse, function, purpose or the like.

The use of any and all examples, or exemplary language (“e.g.,” “suchas,” or the like) provided herein, is intended merely to betterilluminate the embodiments and does not pose a limitation on the scopeof the embodiments. No language in the specification should be construedas indicating any unclaimed element as essential to the practice of theembodiments.

Various exemplary devices and methods are provided for performinglaparoscopic and minimally invasive surgical procedures. However, thereader will readily appreciate that the various methods and devicesdisclosed herein can be used in numerous surgical procedures andapplications including, for example, in connection with open surgicalprocedures. As the present Detailed Description proceeds, the readerwill further appreciate that the various instruments disclosed hereincan be inserted into a body in any way, such as through a naturalorifice, through an incision or puncture hole formed in tissue, etc. Theworking portions or end effector portions of the instruments can beinserted directly into a patient's body or can be inserted through anaccess device that has a working channel through which the end effectorand elongate shaft of a surgical instrument can be advanced.

It is common practice during various laparoscopic surgical procedures toinsert a surgical end effector portion of a surgical instrument througha trocar that has been installed in the abdominal wall of a patient toaccess a surgical site located inside the patient's abdomen. In itssimplest form, a trocar is a pen-shaped instrument with a sharptriangular point at one end that is typically used inside a hollow tube,known as a cannula or sleeve, to create an opening into the body throughwhich surgical end effectors may be introduced. Such arrangement formsan access port into the body cavity through which surgical end effectorsmay be inserted. The inner diameter of the trocar's cannula necessarilylimits the size of the end effector and drive-supporting shaft of thesurgical instrument that may be inserted through the trocar.

Regardless of the specific type of surgical procedure being performed,once the surgical end effector has been inserted into the patientthrough the trocar cannula, it is often necessary to move the surgicalend effector relative to the shaft assembly that is positioned withinthe trocar cannula in order to properly position the surgical endeffector relative to the tissue or organ to be treated. This movement orpositioning of the surgical end effector relative to the portion of theshaft that remains within the trocar cannula is often referred to as“articulation” of the surgical end effector. A variety of articulationjoints have been developed to attach a surgical end effector to anassociated shaft in order to facilitate such articulation of thesurgical end effector. As one might expect, in many surgical procedures,it is desirable to employ a surgical end effector that has as large arange of articulation as possible.

Due to the size constraints imposed by the size of the trocar cannula,the articulation joint components must be sized so as to be freelyinsertable through the trocar cannula. These size constraints also limitthe size and composition of various drive members and components thatoperably interface with the motors and/or other control systems that aresupported in a housing that may be handheld or comprise a portion of alarger automated system. In many instances, these drive members mustoperably pass through the articulation joint to be operably coupled toor operably interface with the surgical end effector. For example, onesuch drive member is commonly employed to apply articulation controlmotions to the surgical end effector. During use, the articulation drivemember may be unactuated to position the surgical end effector in anunarticulated position to facilitate insertion of the surgical endeffector through the trocar and then be actuated to articulate thesurgical end effector to a desired position once the surgical endeffector has entered the patient.

Thus, the aforementioned size constraints form many challenges todeveloping an articulation system that can effectuate a desired range ofarticulation, yet accommodate a variety of different drive systems thatare necessary to operate various features of the surgical end effector.Further, once the surgical end effector has been positioned in a desiredarticulated position, the articulation system and articulation jointmust be able to retain the surgical end effector in that locked positionduring the actuation of the end effector and completion of the surgicalprocedure. Such articulation joint arrangements must also be able towithstand external forces that are experienced by the end effectorduring use.

A variety of surgical end effectors exist that are configured to cut andstaple tissue. Such surgical end effectors commonly include a first jawfeature that supports a surgical staple cartridge and a second jaw thatcomprises an anvil. The jaws are supported relative to each other suchthat they can move between an open position and a closed position toposition and clamp target tissue therebetween. Many of these surgicalend effectors employ an axially moving firing member. In some endeffector designs, the firing member is configured to engage the firstand second jaws such that as the firing member is initially advanceddistally, the firing member moves the jaws to the closed position. Otherend effector designs employ a separate closure system that isindependent and distinct from the system that operates the firingmember.

The staple cartridge comprises a cartridge body. The cartridge bodyincludes a proximal end, a distal end, and a deck extending between theproximal end and the distal end. In use, the staple cartridge ispositioned on a first side of the tissue to be stapled and the anvil ispositioned on a second side of the tissue. The anvil is moved toward thestaple cartridge to compress and clamp the tissue against the deck.Thereafter, staples removably stored in the cartridge body can bedeployed into the tissue. The cartridge body includes staple cavitiesdefined therein wherein staples are removably stored in the staplecavities. The staple cavities are arranged in six longitudinal rows.Three rows of staple cavities are positioned on a first side of alongitudinal slot and three rows of staple cavities are positioned on asecond side of the longitudinal slot. Other arrangements of staplecavities and staples may be possible.

The staples are supported by staple drivers in the cartridge body. Thedrivers are movable between a first, or unfired position, and a second,or fired, position to eject the staples from the staple cavities. Thedrivers are retained in the cartridge body by a retainer which extendsaround the bottom of the cartridge body and includes resilient membersconfigured to grip the cartridge body and hold the retainer to thecartridge body. The drivers are movable between their unfired positionsand their fired positions by a sled. The sled is movable between aproximal position adjacent the proximal end and a distal positionadjacent the distal end. The sled comprises a plurality of rampedsurfaces configured to slide under the drivers and lift the drivers, andthe staples supported thereon, toward the anvil.

Further to the above, in these surgical end effectors, the sled is moveddistally by the firing member. The firing member is configured tocontact the sled and push the sled toward the distal end. Thelongitudinal slot defined in the cartridge body is configured to receivethe firing member. The anvil also includes a slot configured to receivethe firing member. The firing member further comprises a first cam whichengages the first jaw and a second cam which engages the second jaw. Asthe firing member is advanced distally, the first cam and the second camcan control the distance, or tissue gap, between the deck of the staplecartridge and the anvil. The firing member also comprises a knifeconfigured to incise the tissue captured intermediate the staplecartridge and the anvil. It is desirable for the knife to be positionedat least partially proximal to the ramped surfaces such that the staplesare ejected ahead of the knife.

Many surgical end effectors employ an axially movable firing beam thatis attached to the firing member and is used to apply axial firing andretraction motions to the firing member. Many of such firing beamscomprise a laminated construction that affords the firing beam with somedegree of flexure about the articulation joint. As the firing beamtraverses the articulation joint, the firing beam can applyde-articulation forces to the joint and can cause the beam to buckle. Toprevent the firing beam from buckling under pressure, the articulationjoint is commonly provided with lateral supports or “blow-out” platefeatures to support the portion of the beam that traverses thearticulation joint. To advance the firing beam through an angle ofgreater than sixty degrees, for example, a lot of axial force isrequired. This axial force must be applied to the firing member in abalanced manner to avoid the firing member from binding with the jaws asthe firing member moves distally. Any binding of the firing member withthe jaws can lead to component damage and wear as well as require anincreased amount of axial drive force to drive the firing member throughthe clamped tissue.

Other end effector designs employ a firing member that is rotarypowered. In many of such designs, a rotary drive shaft extends throughthe articulation joint and interfaces with a rotatable firing memberdrive shaft that is rotatably supported within one of the jaws. Thefiring member threadably engages the rotatable firing member drive shaftand, as the rotatable firing member drive shaft is rotated, the firingmember is driven through the end effector. Such arrangements require thesupporting jaw to be larger to accommodate the firing member driveshaft. In such devices, a lower end of the firing member commonlyoperably interfaces with the drive shaft which can also result in anapplication of forces that tend to unbalance the firing member as it isdriven distally.

FIGS. 1-4 illustrate one form of a surgical instrument 10 that mayaddress many of the challenges facing surgical instruments witharticulatable end effectors that are configured to cut and fastentissue. In various embodiments, the surgical instrument 10 may comprisea handheld device. In other embodiments, the surgical instrument 10 maycomprises an automated system sometimes referred to as arobotically-controlled system, for example. In various forms, thesurgical instrument 10 comprises a surgical end effector 1000 that isoperably coupled to an elongate shaft assembly 2000. The elongate shaftassembly 2000 may be operably attached to a housing 2002. In oneembodiment, the housing 2002 may comprise a handle that is configured tobe grasped, manipulated, and actuated by the clinician. In otherembodiments, the housing 2002 may comprise a portion of a robotic systemthat houses or otherwise operably supports at least one drive systemthat is configured to generate and apply at least one control motionwhich could be used to actuate the surgical end effectors disclosedherein and their respective equivalents. In addition, various componentsmay be “housed” or contained in the housing or various components may be“associated with” a housing. In such instances, the components may notbe contained with the housing or supported directly by the housing. Forexample, the surgical instruments disclosed herein may be employed withvarious robotic systems, instruments, components and methods disclosedin U.S. Pat. No. 9,072,535, entitled SURGICAL STAPLING INSTRUMENTS WITHROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, which is incorporated byreference herein in its entirety.

In one form, the surgical end effector 1000 comprises a first jaw 1100and a second jaw 1200. In the illustrated arrangement, the first jaw1100 comprises an elongate channel 1110 that comprises a proximal end1112 and a distal end 1114 and is configured to operably support asurgical staple cartridge 1300 therein. The surgical staple cartridge1300 comprises a cartridge body 1302 that has an elongate slot 1304therein. A plurality of surgical staples or fasteners 1305 are storedtherein on drivers 1303 that are arranged in rows on each side of theelongate slot 1304. The drivers 1303 are each associated withcorresponding staple cavities 1308 that open through a cartridge decksurface 1306 and are driven therein upon contact with a sled 1312. Thesurgical staple cartridge 1300 may be replaced after thestaples/fasteners 1305 have been discharged therefrom. See FIG. 6 .Other embodiments are contemplated wherein the elongate channel 1110and/or the entire surgical end effector 1000 may is discarded after thesurgical staple cartridge 1300 has been used. Such end effectorarrangements may be referred to as “disposable loading units”, forexample.

In the illustrated arrangement, the second jaw 1200 comprises an anvil1210 that comprises an elongate anvil body 1212 that comprises aproximal end 1214 and a distal end 1216. In one arrangement, a pair ofstiffening rods or members 1213 may be supported in the anvil body 1212to provide the anvil body 1212 with added stiffness and rigidity. Theanvil body 1212 comprises a staple-forming undersurface 1218 that facesthe first jaw 1100 and may include a series of staple-forming pockets(not shown) that corresponds to each of the staples or fasteners in thesurgical staple cartridge 1300. The anvil body 1212 may further includea pair of downwardly extending tissue stop features 1220 that are formedadjacent the proximal end 1214 of the anvil body 1212. One tissue stopfeature 1220 extends from each side of the anvil body 1212 such that adistal end 1222 on each tissue stop corresponds to the proximal-moststaples/fasteners in the surgical staple cartridge 1300. When the anvil1210 is moved to a closed position onto tissue positioned between thestaple-forming undersurface 1218 of the anvil 1210 and the cartridgedeck surface 1306 of the surgical staple cartridge 1300, the tissuecontacts the distal ends 1222 of the tissue stop features 1220 toprevent the tissue from migrating proximally past the proximal-moststaples/fasteners to thereby ensure that the tissue that is cut is alsostapled. When the surgical staple cartridge is “fired” as will bediscussed in further detail below, the staples/fasteners supportedwithin each staple cavity are driven out of the staple cavity 1308through the clamped tissue and into forming contact with thestaple-forming undersurface 1218 of the anvil 1210.

As can be seen in FIGS. 5 and 6 , the proximal end 1214 of the anvilbody 1212 comprises an anvil mounting portion 1230 that includes a pairof laterally extending mounting pins 1232 that are configured to bereceived in corresponding mounting cradles or pivot cradles 1120 formedin the proximal end 1112 of the elongate channel 1110. The mounting pins1232 are pivotally retained within the mounting cradles 1120 by an anvilcap 1260 that may be attached to the proximal end 1112 of the elongatechannel 1110 by mechanical snap features 1261 that are configured toengage retention formations 1113 on the elongate channel 1110. See FIG.5 . In other arrangements, the anvil cap 1260 may be attached to theelongate channel 1110 by welding, adhesive, etc. Such arrangementfacilitates pivotal travel of the anvil 1210 relative to the surgicalstaple cartridge 1300 mounted in the elongate channel 1110 about a pivotaxis PA between an open position (FIG. 1 ) and a closed position (FIGS.2-5 ). Such pivot axis PA may be referred to herein as being “fixed” inthat the pivot axis does not translate or otherwise move as the anvil1200 is pivoted from an open position to a closed position.

In the illustrated arrangement, the elongate shaft assembly 2000 definesa shaft axis SA and comprises a proximal shaft portion 2100 that mayoperably interface with a housing of the control portion (e.g., handheldunit, robotic tool driver, etc.) of the surgical instrument 10. Theelongate shaft assembly 2000 further comprises an articulation joint2200 that is attached to the proximal shaft portion 2100 and thesurgical end effector 1000. In various instances, the proximal shaftportion 2100 comprises a hollow outer tube 2110 that may be operablycoupled to a housing 2002. See FIG. 2 . As can be seen in FIG. 6 , theproximal shaft portion 2100 may further comprise a rigid proximalsupport shaft 2120 that is supported within the hollow outer tube 2110and extends from the housing to the articulation joint 2200. Theproximal support shaft 2120 may comprise a first half 2120A and a secondhalf 2120B that may be coupled together by, for example, welding,adhesive, etc. The proximal support member 2120 comprises a proximal end2122 and a distal end 2124 and includes an axial passage 2126 thatextends therethrough from the proximal end 2122 to the distal end 2124.

As was discussed above, many surgical end effectors employ a firingmember that is pushed distally through a surgical staple cartridge by anaxially movable firing beam. The firing beam is commonly attached to thefiring member in the center region of the firing member body. Thisattachment location can introduce an unbalance to the firing member asit is advanced through the end effector. Such unbalance can lead toundesirable friction between the firing member and the end effectorjaws. The creation of this additional friction may require anapplication of a higher firing force to overcome such friction as wellas can cause undesirable wear to portions of the jaws and/or the firingmember. An application of higher firing forces to the firing beam mayresult in unwanted flexure in the firing beam as it traverses thearticulation joint. Such additional flexure may cause the articulationjoint to de-articulate—particularly when the surgical end effector isarticulated at relatively high articulation angles. The surgicalinstrument 10 employs a firing system 2300 that may address many if notall of these issues as well as others.

As can be seen in FIGS. 5-11 , in at least one embodiment, the firingsystem 2300 comprises a firing member 2310 that includes avertically-extending firing member body 2312 that comprises a top firingmember feature 2320 and a bottom firing member feature 2350. A tissuecutting blade 2314 is attached to or formed in the vertically-extendingfiring member body 2312. See FIGS. 9 and 11 . In at least onearrangement, it is desirable for the firing member 2310 to pass throughthe anvil body 1212 with low friction, high strength and high stiffness.In the illustrated arrangement, the top firing member feature 2320comprises a top tubular body 2322 that has a top axial passage 2324extending therethrough. See FIG. 10 . The bottom firing member feature2350 comprises a bottom tubular body 2352 that has a bottom axialpassage 2354 extending therethrough. In at least one arrangement, thetop firing member feature 2320 and the bottom firing member feature 2350are integrally formed with the vertically-extending firing member body2312. As can be seen in FIG. 12 , the anvil body 1212 comprises anaxially extending anvil slot 1240 that has a cross-sectional shape thatresembles a “keyhole”. Similarly, the elongate channel 1110 comprises anaxially extending channel slot 1140 that also has a keyholecross-sectional shape.

Traditional firing member arrangements employ long flexible cantileverwings that extend from a top portion and a bottom portion of the firingmember. These cantilever wings slidably pass through slots in the anviland channel that are commonly cut with a rectangular t-cutter whichtended to produce higher friction surfaces. Such long cantilever wingshave minimum surface area contact with the anvil and channel and canresult in galling of those components. The keyhole-shaped channel slot1140 and keyhole-shaped anvil slot 1240 may be cut with a round t-cutterand may be finished with a reamer/borer which will result in thecreation of a lower friction surface. In addition, the top tubular body2322 and the bottom tubular body 2352 tend to be stiffer than the priorcantilever wing arrangements and have increased surface area contactwith the anvil and channel, respectively which can reduce galling andlead to a stronger sliding connection. Stated another way, because theanvil slot 1240 and the channel slot 1140 are keyhole-shaped and haveless material removed than a traditional rectangular slot, the geometryand increased material may result in a stiffer anvil and channel whencompared to prior arrangements.

Turning to FIGS. 9-11 , in one arrangement, the firing system 2300further comprises an upper flexible spine assembly 2400 that is operablycoupled to the top firing member feature 2320 and a lower flexible spineassembly 2500 that is operably coupled to the bottom firing memberfeature 2350. In at least one embodiment, the upper flexible spineassembly 2400 comprises an upper series 2410 of upper vertebra members2420 that are loosely coupled together by an upper flexible couplermember 2402 that is attached to the top firing member feature 2320. Theupper flexible coupler member 2402 may comprises a top cable 2404 thatextends through the top axial passage 2324 in the top firing memberfeature 2320 and a distal end 2406 of the top cable 2404 is attached toa retainer ferrule 2408 that is secured with the top axial passage 2324.

As can be seen in FIG. 13 , each upper vertebra member 2420 comprises anupper vertebra body portion 2422 that has a proximal end 2424 and adistal end 2428. An upper hollow passage 2429 extends through the uppervertebra body portion 2422 to accommodate passage of the upper flexiblecoupler member 2402 therethrough. Each upper vertebra member 2420further comprises a downwardly extending upper drive feature or uppervertebra member tooth 2450 that protrudes from the upper vertebra bodyportion 2422. Each upper vertebra member tooth 2450 has a helix-shapedproximal upper face portion 2452 and a helix-shaped distal upper faceportion 2454. Each proximal end 2424 of the upper vertebra body portions2422 has an upper proximal mating feature 2426 therein and each distalend 2428 has an upper distal mating feature 2430 formed therein. In atleast one embodiment, the upper proximal mating feature 2426 comprises aconcave recess 2427 and each upper distal mating feature 2430 comprisesa convex mound 2431. When arranged in the upper series 2410, the convexmound 2431 on one upper vertebra member 2420 contacts and mates with theconcave recess 2427 on an adjacent upper vertebra member 2420 in theupper series 2410 to maintain the upper vertebra members 2420 roughly inalignment so that the helix-shaped proximal upper face portion 2452 anda helix-shaped distal upper face portion 2454 on each respective uppertooth 2450 can be drivingly engaged by a rotary drive screw 2700 as willbe discussed in further detail below.

Similarly, in at least one embodiment, the lower flexible spine assembly2500 comprises a lower series 2510 of lower vertebra members 2520 thatare loosely coupled together by a lower flexible coupler member 2502that is attached to the bottom firing member feature 2350. The lowerflexible coupler member 2502 may comprises a lower cable 2504 thatextends through the bottom axial passage 2354 in the bottom firingmember feature 2350 and a distal end 2506 of the bottom cable 2504 isattached to a retainer ferrule 2508 that is secured with the bottomaxial passage 2354.

As can be seen in FIG. 14 , each lower vertebra member 2520 comprises alower vertebra body portion 2522 that has a proximal end 2524 and adistal end 2528. A lower hollow passage 2529 extends through the lowervertebra body portion 2522 to accommodate passage of the lower flexiblecoupler member 2502 therethrough. Each lower vertebra member 2520further comprises an upwardly extending lower drive feature or lowervertebra member tooth 2550 that protrudes upward from the lower vertebrabody portion 2522. Each lower vertebra member tooth 2550 has ahelix-shaped proximal lower face portion 2552 and a helix-shaped distallower face portion 2554. Each proximal end 2524 of the lower vertebrabody portions 2522 has a lower proximal mating feature 2526 therein andeach distal end 2528 has a lower distal mating feature 2530 formedtherein. In at least one embodiment, the lower proximal mating feature2526 comprises a concave recess 2527 and each lower distal matingfeature 2530 comprises a convex mound 2531. When arranged in the lowerseries 2510, the convex mound 2531 on one lower vertebra member 2520contacts and mates with the concave recess 2527 on an adjacent lowervertebra member 2520 in the lower series 2510 to maintain the lowervertebra members 2520 roughly in alignment so that the helix-shapedproximal lower face portion 2552 and a helix-shaped distal lower faceportion 2554 on each respective lower vertebra member tooth 2550 can bedrivingly engaged by a rotary drive screw 2700 as will be discussed infurther detail below.

Now turning to FIGS. 5, 7, and 8 , in at least one arrangement, thefiring drive system 2300 further comprises a rotary drive screw 2700that is configured to drivingly interface with the upper series 2410 ofupper vertebra members 2420 and the lower series 2510 of lower vertebramembers 2520. In the illustrated arrangement, the rotary drive screw2700 is driven by a rotary drive system 2600 that comprises a proximalrotary drive shaft 2610 that is rotatably supported within the axialpassage 2126 within the proximal support shaft 2120. See FIG. 7 . Theproximal rotary drive shaft 2610 comprises a proximal end 2612 and adistal end 2614. The proximal end 2612 may interface with a gear box2004 or other arrangement that is driven by a motor 2006 or other sourceof rotary motion housed in the housing of the surgical instrument. SeeFIG. 2 . Such source of rotary motion causes the proximal rotary driveshaft to rotate about the shaft axis SA within the axial passage 2126 inthe proximal support shaft 2120.

The proximal rotary drive shaft 2610 is operably supported within theelongate shaft assembly 2000 in a location that is proximal to thearticulation joint 2200 and operably interfaces with a constant velocity(CV) drive shaft assembly 2620 that spans or extends axially through thearticulation joint 2200. As can be seen in FIGS. 8, 16, and 17 , in atleast one arrangement, the CV drive shaft assembly 2620 comprises aproximal CV drive assembly 2630 and a distal CV drive shaft 2670. Theproximal CV drive assembly 2630 comprises a proximal shaft segment 2632that consists of an attachment shaft 2634 that is configured to benon-rotatably received within a similarly-shaped coupler cavity 2616 inthe distal end 2614 of the proximal rotary drive shaft 2610. Theproximal shaft segment 2632 operably interfaces with a series 2640 ofmovably coupled drive joints 2650.

As can be seen in FIG. 18 , in at least one arrangement, each drivejoint 2650 comprises a first or distal sphere portion 2660 and a secondor proximal sphere portion 2652. The distal sphere portion 2660 islarger than the proximal sphere portion 2652. The distal sphere portion2660 comprises a socket cavity 2662 that is configured to rotatablyreceive a proximal sphere portion 2652 of an adjacent drive joint 2650therein. Each proximal sphere portion 2652 comprises a pair ofdiametrically opposed joint pins 2654 that are configured to be movablyreceived in corresponding pin slots 2664 in the distal sphere portion2660 of an adjacent drive joint 2650 as can be seen in FIG. 16 . Aproximal sphere portion 2652P of a proximal-most drive joint 2650P isrotatably received in a distal socket portion 2636 of the proximal shaftsegment 2632 as shown in FIG. 16 . The joint pins 2654P are receivedwithin corresponding pin slots 2637 in the distal socket portion 2636.As can be further seen in FIG. 16 , a distal-most drive joint 2650D inthe series 2640 of movably coupled drive joints 2650 is movably coupledto a distal CV drive shaft 2670.

In at least one arrangement, the distal CV drive shaft 2670 comprises aproximal sphere portion 2672 that is sized to be movably received in thesocket cavity 2662D in the distal-most drive joint 2650D. The proximalsphere portion 2672 includes joint pins 2674 that are movably receivedin the pin slots 2664D in the distal-most drive joint 2650D. The distalCV drive shaft 2670 further comprises a distally extending shaft stem2676 that is configured to be non-rotatably coupled to the rotary drivescrew 2700 that is positioned distal to the articulation joint 2200. Thedistal CV drive shaft 2670 includes a flange 2677 and a mounting barrelportion 2678 for receiving a thrust bearing housing 2680 thereon.

In the illustrated arrangement, when the series 2640 of movably coupleddrive joints 2650 articulates, the joint pins 2674 remain in thecorresponding pin slots 2664 of an adjacent drive joint 2650. In theexample illustrated in FIG. 18 , each drive joint may be capable ofapproximately eighteen degrees of articulation in the pitch and yawdirections. FIG. 16 illustrates an angle of the series of 2640 of drivejoints 2650 when each drive joint 2650 in the series are fullyarticulated ninety degrees in pitch and yaw which yields an angle α ofapproximately 100.9 degrees. In such arrangement, the outer surface ofeach distal sphere portion 2660 clears the outer surface of the adjacentor adjoining proximal sphere portion 2652 allowing for unrestrictedmotion until the eighteen degree limit is reached. The rigid design andlimited small angles allow the series 2640 of movably coupled drivejoints 2650 to carry high loads torsionally at an overall large angle.

In the illustrated arrangement, the articulation joint 2200 comprises anarticulation joint spring 2230 that is supported within an outerelastomeric joint assembly 2210. The outer elastomeric joint assembly2210 comprises a distal end 2212 that is attached to the proximal end1112 of the elongate channel 1110. For example, as can be seen in FIG. 6, the distal end 2212 of the outer elastomeric joint assembly 2210 isattached to the proximal end 1112 of the elongate channel 1110 by a pairof cap screws 2722 that extend through a distal mounting bushing 2720 tobe threadably received in the proximal end 1112 of the elongate channel1110. A proximal end 2214 of the elastomeric joint assembly 2210 isattached to the distal end 2124 of the proximal support shaft 2120. Theproximal end 2214 of the elastomeric joint assembly 2210 is attached tothe distal end 2124 of the proximal support member 2120 by a pair of capscrews 2732 that extend through a proximal mounting bushing 2750 to bethreadably received in threaded inserts 2125 mounted within the distalend 2124 of the proximal support shaft 2120.

To prevent the drive joints 2650 from buckling during articulation, theseries 2640 of movably coupled drive joints 2650 extend through at leastone low friction articulation joint spring 2730 that is supported withinthe outer elastomeric joint assembly 2210. See FIG. 19 . Thearticulation joint spring 2730 is sized relative to the drive joints2650 such that a slight radial clearance is provided between thearticulation joint spring 2730 and the drive joints 2650. Thearticulation joint spring 2730 is designed to carry articulation loadsaxially which may be significantly lower than the torsional firingloads. The joint spring(s) is longer than the series 2640 of drivejoints 2650 such that the drive joints are axially loose. If the “hardstack” of the series 2640 of drive joints 2650 is longer than thearticulation joint spring(s) 2730 hard stack, then the drive joints 2650may serve as an articulation compression limiter causing firing loadsand articulation loads to resolve axially through the series 2640 of thedrive joints 2650. When the firing loads resolve axially through theseries 2640 of the drive joints 2650, the loads may try to straightenthe articulation joint 2200 or in other words cause de-articulation. Ifthe hard stack of the articulation joint spring(s) 2730 is longer thanthe hard stack of the series 2640 of the drive joints 2650, the firingloads will then be contained within the end effector and no firing loadswill resolve through the drive joints 2650 or through the springs(s)2730.

To further ensure that the drive joints 2650 are always engaged witheach other, a proximal drive spring 2740 is employed to apply an axialbiasing force to the series 2640 of drive joints 2650. For example, ascan be seen in FIGS. 8, 19, and 20 , the proximal drive spring 2740 ispositioned between the proximal mounting bushing 2734 and a supportflange that is formed between the distal socket portion 2636 and aproximal barrel portion 2638 of the proximal shaft segment 2632. In onearrangement, the proximal drive spring 2740 may comprise an elastomericO-ring/bushing received on the proximal barrel portion 2638 of theproximal shaft segment 2632. The proximal drive spring 2740 lightlybiases the drive joints 2650 together to decrease any gaps that mayoccur during articulation. This ensures that the drive joints 2650transfer loads torsionally. It will be appreciated, however, that in atleast one arrangement, the proximal drive spring 2740 does not apply ahigh enough axial load to cause firing loads to translate through thearticulation joint 2200.

As can be seen in FIGS. 9 and 10 , the top firing member feature 2320 onthe firing member 2310 comprises a distal upper firing member toothsegment 2330 that is equivalent to one half of an upper tooth 2450 oneach upper vertebra member 2420. In addition, a proximal upper firingmember tooth 2336 that is identical to an upper tooth 2450 on each uppervertebra member 2420 is spaced from the distal upper firing member toothsegment 2330. The distal upper firing member tooth segment 2330 and theproximal upper firing member tooth 2336 may be integrally formed withthe top firing member feature 2320 of the firing member 2310. Likewise,the bottom firing member feature 2350 of the firing member 2310comprises a distal lower firing member tooth 2360 and a proximal lowerfiring member tooth 2366 that are integrally formed on the bottom firingmember feature 2350. For example, in at least one arrangement, thefiring member 2310 with the rigidly attached teeth 2330, 2336, 2360, and2366 may be fabricated at one time as one unitary component usingconventional metal injection molding techniques.

As indicated above, each of the upper vertebra members 2520 is movablyreceived on an upper flexible coupler member 2402 in the form of a topcable 2404. As was described above, the distal end 2406 of the top cable2404 is secured to the top firing member feature 2320 of the firingmember 2310. Similarly, each of the lower vertebra members 2520 ismovably received on a lower flexible coupler member 2502 in the form ofa lower cable 2504. A distal end 2506 of the lower cable 2504 is securedto the bottom firing member feature 2350 of the firing member 2310. Inat least one arrangement, the top cable 2404 and the bottom cable 2504extend through the proximal shaft portion 2100 and, as will be discussedin further detail below, may interface with a bailout arrangementsupported in the housing for retracting the firing member 2310 back toits home or starting position should the firing member drive systemfail.

Turning again to FIG. 8 , the axial length AL_(u) of the upper series2410 of upper vertebra members 2420 and the axial length AL₁ of thelower series 2510 of lower vertebra members 2520 are equal and must besufficiently long enough to facilitate the complete distal advancementof the firing member 2310 from the home or starting position to adistal-most ending position within the staple cartridge while theproximal-most upper vertebra members 2420 in the upper series 2410 ofupper vertebra members 2420 and the proximal-most lower vertebra members2520 in the lower series 2510 of lower vertebra members 2520 remain indriving engagement with the rotary drive screw 2700. As can be seen inFIG. 8 , an upper compression limiting spring 2421 is configured tointerface with a proximal-most upper vertebra member 2420P in the upperseries 2410 of upper vertebra members 2420. The upper compressionlimiting spring 2421 is journaled on the top cable 2404 and is retainedin biasing engagement with the proximal-most upper vertebra member 2420Pby an upper spring holder 2423 that is retained in position by an upperferrule 2425 that is crimped onto the top cable 2404. The top cable 2404extends through an upper hypotube 2433 that is supported in the proximalsupport shaft. Likewise, a lower compression limiting spring 2521 isconfigured to interface with a proximal-most, lower vertebra member2520P in the lower series 2510 of lower vertebra members 2520. The lowercompression spring 2521 is journaled on the lower cable 2504 and isretained in biasing engagement with the proximal-most, lower vertebramember 2520P by a lower spring holder 2523 that is retained in positionby a lower ferrule 2525 that is crimped onto the lower cable 2504. Thelower cable 2504 extends through a lower hypotube 2533 that is supportedin the proximal support shaft.

When the upper vertebra members 2420 and the lower vertebra members 2520angle through the articulation joint (after the end effector has beenpositioned in an articulated position), the gaps between the respectivevertebra members 2420, 2520 increase in each series 2410, 2510 whichcauses the springs 2421, 2521 to become tighter. The compressionlimiting springs 2421, 2521 provide enough slack in the cables 2404,2504, respectively to enable the vertebra members 2420, 2520 anglethrough the most extreme articulation angles. If the cables 2404, 2504are pulled too tight, the spring holders 2423, 2523 will contact theirrespective proximal-most vertebra members 2420P, 2520P. Such compressionlimiting arrangements ensure that the vertebra members 2420, 2520 intheir respective series 2410, 2510 always remain close enough togetherso that the rotary drive screw 2700 will always drivingly engage them inthe manner discussed in further detail below. When the vertebra members2420, 2520 are aligned straight again, the compression limiting springs2421, 2521 may partially relax while still maintaining some compressionbetween the vertebra members.

As indicated above, when the upper vertebra members 2420 are arranged inthe upper series 2410 and lower vertebra members 2520 are arranged inthe lower series 2510, the convex mounds and concave recesses in eachvertebra member as well as the compression limiter springs serve tomaintain the upper and lower vertebra members in relatively linearalignment for driving engagement by the rotary drive screw 2700. As canbe seen in FIGS. 9 and 10 , when the upper vertebra members 2420 are inlinear alignment, the upper teeth 2450 are spaced from each other by anopening space generally designated as 2460 that facilitates drivingengagement with the helical drive thread 2170 on the rotary drive screw.Similarly, when the lower vertebra members 2520 are in linear alignment,the lower vertebra member teeth 2550 are spaced from each other by anopening space generally designated as 2560 that facilitates drivingengagement with the helical drive thread 2170 of the rotary drive screw2700.

Turning to FIGS. 8 and 22 , the rotary drive screw 2700 comprises ascrew body 2702 that has a socket 2704 therein for receiving thedistally extending shaft stem 2676 of the distal CV drive shaft 2670. Aninternal radial groove 2714 (FIG. 10 ) is formed in the screw body 2702for supporting a plurality of ball bearings 2716 therein. In onearrangement, for example, 12 ball bearings 2716 are employed. The radialgroove 2714 supports the ball bearings 2716 between the screw body 2702and a distal end of the thrust bearing housing 2680. The ball bearings2716 serve to distribute the axial load of the rotary drive screw 2700and significantly reduce friction through the balls' rolling motion.

As can be seen in FIG. 23 , a helical drive thread 2710 is providedaround the screw body 2702 and serves to form a proximal thread scoopfeature 2712. The proximal thread scoop feature 2712 is formed with afirst pitch 2713 and the remaining portion of the helical drive thread2710 is formed with a second pitch 2715 that differs from the firstpitch 2713. In FIGS. 22 and 23 , area 2718 illustrates where the firstpitch 2713 and the second pitch 2715 converge. In at least oneembodiment, the first pitch 2713 is larger than the second pitch 2715 toensure that the rotary drive screw 2700 captures and “scoops up” ordrivingly engages every upper vertebra member 2420 and every lowervertebra member 2520. As can be seen in FIG. 24 , a proximal end 2717 ofthe helical drive thread 2710 that has the first pitch 2713 has scoopedinto the into the opening space 2560 between two adjacent lower vertebramember teeth 2550A and 2550B while the center portion 2719 of thehelical drive thread 2710 that has the second pitch 2715 is in drivingengagement with the helix-shaped distal lower face portion 2554 on thelower vertebra member tooth 2550B and the helix-shaped proximal lowerface portion 2552 on the proximal lower firing member tooth 2366. As canalso be appreciated, the scoop feature 2712 may not contact thehelix-shaped distal lower face portion 2554A of the lower vertebramember tooth 2550A as it scoops up the lower vertebra member tooth 2550Bwhen driving the firing member 2310 distally. The helical drive thread2710 interacts with the teeth 2450 of the upper vertebra members 2420 ina similar manner.

A power screw is a threaded rod with a full three hundred sixty degreenut around it. Rotation of the power screw causes the nut to advance ormove longitudinally. In the present arrangements, however, due to spaceconstraints, a full three hundred sixty degree nut cannot fit inside theend effector. In a general sense, the upper flexible spine assembly 2400and the lower flexible spine assembly 2500 comprise aradially/longitudinally segmented “power screw nut” that is rotatablydriven by the rotary drive screw 2700. When the rotary drive screw isrotated in a first rotary direction, the rotary drive screw 2700 drivesone or more vertebra members in each of the upper series and lowerseries of vertebra members longitudinally while the vertebra members2420, 2520 stay in the same locations radially. The upper series 2410and lower series 2510 are constrained from rotating around the rotarydrive screw 2700 and can only move longitudinally. In one arrangement,the upper vertebra members 2420 in the upper series 2410 and the lowervertebra members 2520 in the lower series 2510 only surround the rotarydrive screw 2700 with less than ten degrees each.

FIG. 25 illustrates the firing member 2310 in the home or startingposition. As can be seen in FIG. 25 , a portion of the helical drivethread 2710 on the rotary drive screw 2700 is engaged between the distalupper firing member tooth segment 2330 and the proximal upper firingmember tooth 2336 and another portion of the helical drive thread 2710is engaged between the distal lower firing member tooth 2360 and aproximal lower firing member tooth 2366 on the firing member 2310. Sucharrangement enables the rotary drive screw 2700 to precisely control thedistal and proximal movement of the firing member 2310 which, as will bediscussed in further detail below, can result in the precise movement ofthe anvil 1210. Once the firing member 2310 has been sufficientlydistally advanced during a firing stroke, the helical drive thread 2710operably engages the teeth on the upper and lower vertebras. See FIG. 26.

The surgical instrument 10 also comprises an articulation system 2240that is configured to apply articulation motions to the surgical endeffector 1000 to articulate the surgical end effector relative to theelongate shaft assembly 2000. In at least one arrangement, for example,the articulation system comprises four articulation cables 2242, 2246,2250, and 2254 that extend through the elongate shaft assembly 2000. SeeFIG. 27 . In the illustrated arrangement, the articulation cables 2242,2246 pass through the proximal mounting bushing 2750, the proximal end2214 of the elastomeric joint assembly 2210, as well as a central ribsegment 2216 to be secured to the distal end 2212 of the elastomericjoint assembly 2210 or other portion of the surgical instrument.Likewise, the articulation cables 2250 and 2254 extend through theproximal mounting bushing 2750, the proximal end 2214 of the elastomericjoint assembly 2210, as well as a central rib segment 2218 to be securedto the distal end 2212 of the elastomeric joint assembly 2210 or otherportion of the surgical end effector. The cables 2242, 2246, 2250, and2254 operably interface with an articulation control system that issupported in the housing of the surgical instrument 10. For example, aproximal portion of each cable 2242, 2246, 2250, and 2254 may be spooledon a corresponding rotary spool or cable-management system 2007 (FIG. 2) in the housing portion of the surgical instrument 10 that isconfigured to payout and retract each cable 2242, 2246, 2250, and 2254in desired manners. The spools/cable management system may be motorpowered or manually powered (ratchet arrangement, etc.). FIG. 29illustrates articulation of the surgical end effector 1000 through afirst articulation plane relative to the elongate shaft assembly 2000.FIG. 30 illustrates articulation of the surgical end effector 1000through a second articulation plane relative to the elongate shaftassembly 2000. FIG. 31 illustrates articulation of the surgical endeffector 1000 through multiple articulation planes relative to theelongate shaft assembly 2000.

FIGS. 32-34 illustrate an alternative articulation joint 2200′ in theform of an elastomeric joint assembly 2210′. As can be seen in FIG. 33 ,each articulation cable passes through a corresponding spring 2215′ thatis mounted in the ribs 2216′ of the elastomeric joint assembly 2210′.For example, cable 2242 extends through spring 2244. Cable 2246 extendsthrough spring 2248. Cable 2250 extends through spring 2252 and cable2254 extends through spring 2256. As indicated above, the end effectoris articulated by pulling on and relaxing the appropriate cables 2242,2246, 2250 and 2254. To achieve higher articulation angles with greaterjoint stability, each of the springs 2244, 2248, 2252, and 2256 canslide through the ribs of the elastomeric joint to push the end effectorand pull on the cables extending therethrough. The springs 2244, 2248,2252, and 2256 will also retract into the ribs when the cables 2242,2246, 2250, and 2254 are pulled tight. Each of the springs 2244, 2248,2252, and 2256 loosely seat over the particular cable that passestherethrough. Each cable and corresponding spring may terminate orotherwise be coupled to a corresponding solid rod that is supported inthe elongate shaft assembly 2000 and may be pushed and pulled from itsproximal end. When the cable is pulled, the corresponding spring wouldcarry little to no load. When the spring is pushed, the cable wouldcarry little load, but will help limit the end effector movement. Thisinteraction between the cable and spring may facilitate higherarticulation angles that may approach ninety degrees, for example.

Because the radially/longitudinally segmented power screw nutarrangement disclosed herein does not have the same constraints as athree hundred sixty degree nut, the upper vertebra members 2420 in theupper series 2410 and the lower vertebra members 2520 in the lowerseries 2510 are constrained to ensure that their loads are transferredto the firing member in a longitudinal direction. To maintain each ofthe upper vertebra members 2420 in the desired orientation and toprevent the upper vertebra members 2420 from becoming snagged ordisoriented when traversing through the articulation joint 2200, theupper vertebra members 2420 are aligned to pass through an upper sleeve2470 that extends through an upper portion of the outer elastomericjoint assembly 2210 of the articulation joint 2200. See FIGS. 27, 28,and 35 . A distal end 2472 of the upper sleeve 2470 is supported in theproximal end 1112 of the elongate channel 1110 and a proximal end 2474of the upper sleeve 2470 is supported in the distal end of the proximalsupport shaft 2120. The upper sleeve 2470 is fabricated from a polymeror plastic material that has a low coefficient of friction and isflexible to enable the upper sleeve 2470 to flex with the outerelastomeric joint assembly 2210. The upper sleeve 2470 protects theupper vertebra members 2420 from contacting the outer elastomeric jointassembly 2210 that is fabricated from an elastomeric material that mayhave a higher coefficient of friction than the coefficient of frictionof the material of the upper sleeve 2470. Stated another way, the uppersleeve 2470 forms a low friction, flexible, continuous, uninterrupted,and fully encapsulating path for the upper vertebra members 2420 as theytraverse the articulation joint 2200.

Similarly, a lower sleeve 2570 is employed to support the lower vertebramembers 2520 as they pass through the articulation joint 2200. A distalend 2572 of the lower sleeve 2570 is supported in the proximal end ofthe elongate channel and a proximal end of the lower sleeve 2570 issupported in the distal end of the proximal support shaft 2120. Like theupper sleeve 2470, the lower sleeve 2570 is fabricated from a polymer orplastic material that has a low coefficient of friction and is flexibleto enable the lower sleeve 2570 to flex with the outer elastomeric jointassembly 2210. The lower sleeve 2570 protects the lower vertebra members2520 from contacting the outer elastomeric joint assembly 2210 as theypass through the articulation joint 2200. Stated another way, the lowersleeve 2570 forms a low friction, flexible, continuous, uninterrupted,and fully encapsulating path for the lower vertebra members 2520 as theytraverse the articulation joint 2200. In various embodiments, the uppersleeve 2470 and the lower sleeve 2570 are configured to bend freelywithout creating a kink. To prevent the formation of kinks in thesleeves, in at least one arrangement, the sleeves 2470, 2570 aresupported within the outer elastomeric joint assembly 2210 such that thesleeves may move axially. For example, when the articulation jointangles up, the lower sleeve 2570 may slide distally and have a largebend radius; the upper sleeve 2470 in the same example, may slideproximally and have a tighter bend radius. By moving axially, the amountof material exposed outside of the joint assembly 2210 which mightotherwise be susceptible to kinking under a tight bend radius isreduced. In at least one arrangement, the distal end 2472 of the uppersleeve 2470 is formed with an upper scoop 2476 that is configured tofunnel the upper vertebra members 2420 into the anvil cap 1260.Similarly, the distal end of the lower sleeve 2570 may be formed with alower scoop that is configured to funnel the lower vertebra members 2520into the channel slot 1140 in the elongate channel 1110.

As indicated above, the anvil mounting portion 1230 comprises a pair oflaterally extending mounting pins 1232 that are configured to bereceived in corresponding mounting cradles or pivot cradles 1120 thatare formed in the proximal end 1112 of the elongate channel 1110. Themounting pins 1232 are pivotally retained within the mounting cradles1120 by an anvil cap 1260 that is attached to the proximal end 1112 ofthe elongate channel 1110 in the above-described manners. The anvil cap1260 comprises a proximal end 1262 and a distal end 1264 and has akeyhole-shaped vertebra passage 1266 extending therethrough toaccommodate passage of the top firing member feature 2320 and uppervertebra members 2420 therethrough. FIG. 36 illustrates the vertebrapassage 1266 in the anvil cap 1260. When the rotary drive screw 2700applies load to the upper vertebra members 2420, the vertebra members2420 will tend to tilt about the area A in FIG. 37 , so the uppervertebra member tooth 2450 is no longer square with the rotary drivescrew 2700 and may instead experience a higher-pressure line contact.Areas B in FIG. 37 show where the upper vertebra member 2420 stopstilting. To ensure that most of the loads stay in the longitudinaldirection to perform useful work, the upper vertebra member tooth 2450must be angled the same amount as the upper vertebra member 2420 tilts.Thus, when the upper vertebra member 2420 tilts, the upper vertebramember tooth 2450 will still maintain surface contact with the helicaldrive member 2710 on the rotary drive screw 2700 and all loads will bedirected longitudinally and not vertically. The slightly angled uppervertebra member tooth 2450 may behave like a square thread when thevertebra member 2420 is tilted and better distributes loads to lower thepressure contact. By directing most of the loads in the longitudinaldirection, vertical loads are avoided which could result in theestablishment of friction that would counter the longitudinal loads. Theupper vertebra members 2420 react similarly as they pass down thekeyhole-shaped anvil slot 1240. Likewise, the lower vertebra members2520 react similarly as they pass through the keyhole-shaped axiallyextending channel slot 1140 in the elongate channel 1110.

In the illustrated arrangement, the anvil 1210 is moved to the openposition by a pair of anvil springs 1270 that are supported within theproximal end of the elongate channel. See FIGS. 38, 42, and 43 . Thesprings 1270 are positioned to apply a pivotal biasing force tocorresponding anvil control arms 1234 that may be integrally formed withanvil mounting portion 1230 and extend downwardly therefrom. See FIG. 38.

FIGS. 39-41 illustrate portions of the anvil 1210, the firing member2310, and the anvil cap 1260 when the anvil 1210 is open (FIG. 39 ),when the anvil 1210 is partially closed (FIG. 40 ) and after the firingmember has been advanced distally from the home or starting position(FIG. 41 ). As can be seen in FIG. 39 , when the firing member 2310 isin the home or starting position, the top firing member feature 2320 iscompletely received within the vertebra passage 1266 in the anvil cap1260. During a firing stroke, the top firing member feature 2320 and theupper vertebra members 2420 in the upper series 2410 must transitionfrom the vertebra passage 1266 in the anvil cap 1260 to thekeyhole-shaped anvil slot 1240. Thus, it is desirable to minimize anygap “G” between the anvil mounting portion 1230 and a distal end 1264 ofthe anvil cap 1260. To minimize this gap G while facilitate unimpededpivotal travel of the anvil 1210, the distal end 1264 of the anvil cap1260 is formed with a curved cap surface 1265 that matches a curvedmating surface 1231 on the anvil mounting portion 1230. Both surfaces1265, 1231 are curved and concentric about the pivot axis PA or someother reference point. Such arrangement allows the anvil 1210 to moveradially and not interfere with the anvil cap 1260 while maintaining aminimal gap G therebetween. The gap G between the anvil mounting portion1230 and the distal end 1264 of the anvil cap 1260 is significantlyshorter than a length of an upper vertebra member 2420 which facilitateseasy transition of each upper vertebra member 2420 from the vertebrapassage 1266 in the anvil cap 1260 to the keyhole-shaped anvil slot1240. In addition, to further assist with the transition of the topfiring member feature 2320 into the keyhole-shaped anvil slot 1240, aramped surface 1241 is formed adjacent the curved mating surface 1231 onthe anvil mounting portion 1230. As the firing member 2310 is initiallyadvanced distally from the home or starting position, a distal end ofthe top firing member feature 2320 contacts the ramped surface 1241 andbegins to apply a closing motion to the anvil 1210 as can be seen inFIG. 40 . Further distal advancement of the firing member 2310 duringthe firing stroke or firing sequence causes the top firing memberfeature to enter the keyhole shaped anvil slot 1240 to completely closethe anvil 1210 and retain the anvil 1210 in the closed position duringthe firing sequence. See FIG. 41 .

In general, the highest firing forces established in an endocutter areassociated with cutting and stapling tissue. If those same forces can beused to close the anvil, then the forces generated during pre-clampingand grasping of tissue can be high as well. In at least one arrangement,the firing member body 2312 further comprises a firing member wing ortab 2355 that extends laterally from each lateral side of the firingmember body 2312. See FIGS. 15 and 36 . The firing member wings 2355 arepositioned to contact the corresponding anvil control arms 1234 when thefiring member 2310 is driven in the proximal direction PD from the homeor starting position to quickly close the anvil 1210 for graspingpurposes. In at least one arrangement, when the firing member 2310 is inthe home or starting position, the firing member wings 2355 are locateddistal to the anvil control arms 1234 as shown in FIG. 42 . When thefiring member 3210 is moved proximally, the firing member wings 2355push the anvil control arms 1234 (pivotal direction C) against the biasof the anvil springs 1270. See FIG. 42 . In one arrangement, the firingmember 2310 only has to move a short distance D to pivot the anvil 1210to a closed position. In one embodiment, distance D may be approximately0.070 inches long, for example. This short movement allows for a quickresponse. Because the anvil pivot point or pivot axis PA is relativelyfar from the firing member wings 2355 which creates a substantial momentarm, the proximal movement of the firing member 2310 (and firing memberwings 2355) results in an application of high pre-compression torque tothe anvil 1210 to move the anvil 1210 to a closed position. Thus, thefiring member wings 2355 may be referred to herein as “pre-compressionfeatures”. See FIG. 43 . Thus, the clinician may use the surgical endeffector 1000 to grasp and manipulate tissue between the anvil 1210 andthe surgical staple cartridge 1300 without cutting the tissue andforming the staples, by advancing the firing member 2310 proximally theshort distance D to cause the anvil 1210 to quickly pivot to a closedposition.

The firing member 2310 may be moved in the proximal direction PD byrotating the rotary drive screw 2700 in a second rotary direction. Thus,when the firing member 2310 is in the “home” or starting position, theanvil 1210 may be biased into the fully open position by the anvilsprings 1270. Activation of the rotary drive system 2600 to apply arotary motion to the rotary drive screw 2700 in a first rotary directionwill cause the firing member 2310 to be advanced distally from the homeor starting position to apply an anvil closure motion to the anvil 1210to move the anvil closed to clamp the target tissue between the anvil1210 and the surgical staple cartridge 1300. Continued rotation of therotary drive screw in the first rotary direction will cause the firingmember 2310 to continue to distally advance through the surgical endeffector 1000. As the firing member 2310 moves distally, the firingmember 2310 (as well as the firing member wings 2355 thereon) contacts asled 1312 (FIG. 19 ) that is supported in the surgical staple cartridge1300 to drive the sled 1312 distally through the staple cartridge body1302. When the firing member 2310 is in the home or starting position,the surgeon may wish to use the surgical end effector to grasp andmanipulate tissue. To do so, the rotary drive system is actuated toapply a second rotary drive motion to the rotary drive screw 2700 in asecond rotary direction that is opposite to the first rotary direction.Such rotary movement of the rotary drive screw 2700 in the second rotarydirection will drive the firing member 2310 proximally from the startingposition and cause the anvil 1210 to quickly pivot to the closedposition. Thus, in accordance with at least one embodiment, the “home orstarting position” of the firing member 2310 is not its proximal-mostposition.

If during the firing process, the rotary drive system 2600 quitsrotating, the firing member 2310 may become stuck within the surgicalend effector. In such instance, the top firing member feature 2320 mayremain engaged with the anvil 1210 and the bottom firing member feature2350 may remain engaged with the elongate channel 1110 and therebyprevent the surgeon from moving the anvil 1210 to an open position torelease the tissue clamped between anvil 1210 and surgical staplecartridge 1300. This could occur, for example, if the motor or othercontrol arrangement supplying the rotary drive motions to the rotarydrive shaft 2610 fails or otherwise becomes inoperative. In suchinstances, the firing member 2310 may be retracted back to the home orstarting position within the surgical end effector 1000 by pulling thetop cable 2404 and the lower cable 2504 in a proximal direction. Forexample, a proximal portion of the top cable 2404 and a proximal portionof the lower cable 2505 may be spooled on a rotary spool orcable-management system 2009 (FIG. 2 ) in the housing portion of thesurgical instrument 10 that is configured to payout the top cable 2404and lower cable 2504 during the firing stroke and also retract thecables 2404, 2504 in a proximal direction should the firing member 2310need to be retracted. The cable management system 2009 may be motorpowered or manually powered (ratchet arrangement, etc.) to applyretraction motions to the cables 2404, 2504. When the cables 2404, 2504are retracted, the upper vertebra members 2420 and lower vertebramembers 2520 will cause the rotary drive screw 2700 to spin in reverse.

The following equation may be used to determine whether the rotary drivescrew 2700 will spin in reverse depending upon the lead (L), pitchdiameter (d_(p)), tooth angle (α) and friction (μ):

$\mu \geq {\frac{L}{\pi d_{p}}\;\cos\;\alpha}$

The rotary drive screw 2700 may self-lock if the above equation is true.For the most part, in many instances, the pitch diameter is mostly fixedfor an endocutter, but the lead and tooth angle are variable. Becausethe upper vertebra member teeth 2450 and lower vertebra member teeth2550 are mostly square, the rotary drive screw 2700 is more likely to beback drivable (cos (90)=1). The leads of the upper vertebra member teeth2450 and lower vertebra member teeth 2550 may also be advantageous inthat the rolling friction between the vertebra members 2420, 2520 andthe rotary drive screw 2700 is more likely to enable the rotary drivescrew 2700 to be back driven. Thus, in the event of an emergency, thesurgeon can pull on the upper and lower cables 2404, 2504 in theproximal direction to cause the firing member 2310 to fully retract fora quick “bailout”.

As indicated above, the relative control motions for the rotary drivesystem 2600, as well as the various cable-management systems employed inconnection with the firing system 2300 and the articulation controlsystem 2240, may be supported within a housing 2002 which may behandheld or comprise a portion of a larger automated surgical system.The firing system 2300, articulation control system 2240, and the rotarydrive system 2600 may, for example, be motor-controlled and operated byone or more control circuits.

One method of using the surgical instrument 10 may involve the use ofthe surgical instrument 10 to cut and staple target tissue within apatient using laparoscopic techniques. For example, one or more trocarsmay have been placed through the abdominal wall of a patient to provideaccess to a target tissue within the patient. The surgical end effector1000 may be inserted through one trocar and one or more cameras or othersurgical instruments may be inserted through the other trocar(s). Toenable the surgical end effector 1000 to pass through the trocarcannula, the surgical end effector 1000 is positioned in anunarticulated orientation and the jaws 1100 and 1200 must be closed. Toretain the jaws 1100 and 1200 in the closed position for insertionpurposes, for example, the rotary drive system 2600 may be actuated toapply the second rotary motion to the rotary drive screw 2700 to causethe firing member 2310 to move proximally from the starting position tomove the anvil 1210 (jaw 1200) to the closed position. See FIG. 44 . Therotary drive system 2600 is deactivated to retain the firing member 2310in that position. Once the surgical end effector has passed into theabdomen through the trocar, the rotary drive system 2600 may beactivated to cause the rotary drive screw 2700 to drive the firingmember 2310 distally back to the starting position wherein the anvilsprings 1270 will pivot the anvil 1210 to the open position. See FIG. 38.

Once inside the abdomen and before engaging the target tissue, thesurgeon may need to articulate the surgical end effector 1000 into anadvantageous position. The articulation control system 2240 is thenactuated to articulate the surgical end effector in one or more planesrelative to a portion of the elongate shaft assembly 2000 that isreceived within the cannula of the trocar. Once the surgeon has orientedthe surgical end effector 1000 in a desirable position, the articulationcontrol system 2240 is deactivated to retain the surgical end effector1000 in the articulated orientation. The surgeon may then use thesurgical end effector to grasp the target tissue or adjacent tissue byactivating the rotary drive system to rotate the rotary drive screw inthe second rotary direction to move the firing member proximally tocause the anvil 1210 to rapidly close to grasp the tissue between theanvil 1210 and the surgical staple cartridge 1300. The anvil 1210 may beopened by reversing the rotation of the rotary drive screw 2700. Thisprocess may be repeated as necessary until the target tissue has beproperly positioned between the anvil 1210 and the surgical staplecartridge 1300.

Once the target tissue has been positioned between the anvil 1210 andthe surgical staple cartridge, the surgeon may commence the closing andfiring process by activating the rotary drive system 2600 to drive thefiring member 2310 distally from the starting position. As the firingmember 2310 moves distally from the starting position, the firing member2310 applies a closure motion to the anvil 1210 and moves the anvil 1210from the open position to the closed position in the manners discussedabove. As the firing member 2310 moves distally, the firing member 2310retains the anvil 1210 in the closed position thereby clamping thetarget tissue between the anvil 1210 and the surgical staple cartridge1300. As the firing member 2310 moves distally, the firing member 2310contacts a sled 1312 supported in the surgical staple cartridge 1300 andalso drives the sled 1312 distally through the staple cartridge body1302. The sled 1312 serially drives rows of drivers supported in thestaple cartridge toward the clamped target tissue. Each driver hassupported thereon one or more surgical staples or fasteners which arethen driven through the target tissue and into forming contact with theunderside of the anvil 1210. As the firing member 2310 moves distally,the tissue cutting edge 2314 thereon cuts through the stapled tissue.

After the firing member 2310 has been driven distally to the endingposition within the surgical end effector 1000 (FIG. 45 ), the rotarydrive system 2600 is reversed which causes the firing member 2310 toretract proximally back to the home or starting position. Once thefiring member 2310 has returned to the starting position, the anvilsprings 1270 will pivot the anvil 1210 to the open position to enablethe surgeon to release the stapled tissue from the surgical end effector1000. Once the stapled tissue has been released, the surgical endeffector may be withdrawn out of the patient through the trocar cannula.To do so, the surgeon must first actuate the articulation control system2240 to return the surgical end effector 1000 to an unarticulatedposition and actuate the rotary drive system to drive the firing member2310 proximally from the home or starting position to close the jaws.Thereafter, the surgical end effector 1000 may be withdrawn through thetrocar cannula. If during the firing process or during the retractionprocess, the firing system becomes inoperative, the surgeon may retractthe firing member 2310 back to the starting position by applying apulling motion to the cables 2404, 2505 in the proximal direction in thevarious manners described herein.

FIGS. 46-68 illustrate another surgical instrument 22010 that in manyaspects is identical or very similar to the surgical instrument 10described above, except for the various differences discussed below.Like surgical instrument 10, surgical instrument 22010 may address manyof the challenges facing surgical instruments with articulatable endeffectors that are configured to cut and fasten tissue. In variousembodiments, the surgical instrument 22010 may comprise a handhelddevice. In other embodiments, the surgical instrument 22010 maycomprises an automated system sometimes referred to as arobotically-controlled system, for example. In various forms, thesurgical instrument 22010 comprises a surgical end effector 23000 thatis operably coupled to an elongate shaft assembly 24000. The elongateshaft assembly 24000 may be operably attached to a housing that ishandheld or otherwise comprises a portion of a robotic system as wasdiscussed above.

As can be seen in FIG. 49 , in one form, the surgical end effector 23000comprises a first jaw 23100 and a second jaw 23200. In the illustratedarrangement, the first jaw 23100 comprises an elongate channel 23110that comprises a proximal end 23112 and a distal end 23114 and isconfigured to operably support a surgical staple cartridge 1300 therein.The elongate channel 23110 has an open bottom to facilitate ease ofassembly and has a channel cover 23113 that is configured to be attachedthereto (welded, etc.) to cover the opening and add rigidity to theelongate channel 23110. In the illustrated arrangement, the second jaw23200 comprises an anvil 23210 that comprises an elongate anvil body23212 that comprises a proximal end 23214 and a distal end 23216. In onearrangement, an anvil cover 23213 is provided to facilitate assembly ofthe device and add rigidity to the anvil 23210 when it is attached(welded, etc.) to the anvil body 23212. The anvil body 23212 comprises astaple-forming undersurface 23218 that faces the first jaw 23100 and mayinclude a series of staple-forming pockets (not shown) that correspondsto each of the staples or fasteners in the surgical staple cartridge1300. The proximal end 23214 of the anvil body 23212 comprises an anvilmounting portion 23230 that includes a pair of laterally extendingmounting pins 23232 that are configured to be received in correspondingmounting cradles or pivot cradles 23120 formed in the proximal end 23112of the elongate channel 23110. The mounting pins 23232 are pivotallyretained within the mounting cradles 23120 by an anvil cap 23260 thatmay be attached to the proximal end 23112 of the elongate channel 23110by screws 23261. In other arrangements, the anvil cap 23260 may beattached to the elongate channel 23110 by welding, adhesive, etc. Sucharrangement facilitates pivotal travel of the anvil 23210 relative tothe surgical staple cartridge 1300 mounted in the elongate channel 23110about a pivot axis PA between an open position (FIG. 47 ) and a closedposition (FIG. 48 ). Such pivot axis PA may be referred to herein asbeing “fixed” in that the pivot axis does not translate or otherwisemove as the anvil 23210 is pivoted from an open position to a closedposition.

In the illustrated arrangement, the anvil 23210 is moved to the openposition by a pair of anvil springs 23270 that are supported within theproximal end 23112 of the elongate channel 23110. See FIGS. 49 and 62 .The springs 23270 are positioned to apply a pivotal biasing force tocorresponding portions of the anvil 23210 to apply opening forcesthereto. See FIG. 47 .

In the illustrated arrangement, the elongate shaft assembly 24000defines a shaft axis SA and comprises a proximal shaft portion 24100that may operably interface with a housing of the control portion (e.g.,handheld unit, robotic tool driver, etc.) of the surgical instrument22010. The elongate shaft assembly 24000 further comprises anarticulation joint 24200 that is attached to the proximal shaft portion24100 and the surgical end effector 23000. In various instances, theproximal shaft portion 24100 comprises a hollow outer tube 24110 thatmay be operably coupled to a housing in the various manners discussedabove. As can be seen in FIG. 49 , the proximal shaft portion 24100 mayfurther comprise a rigid proximal support shaft 24120 that is supportedwithin the hollow outer tube 24110 and extends from the housing to thearticulation joint 24200. The rigid proximal support shaft 24120 maycomprise a first half 24120A and a second half 24120B that may becoupled together by, for example, welding, adhesive, etc. The rigidproximal support shaft 24120 comprises a proximal end 24122 and a distalend 24124 and includes an axial passage 24126 that extends therethroughfrom the proximal end 24122 to the distal end 24124.

As was discussed above, many surgical end effectors employ a firingmember that is pushed distally through a surgical staple cartridge by anaxially movable firing beam. The firing beam is commonly attached to thefiring member in the center region of the firing member body. Thisattachment location can introduce an unbalance to the firing member asit is advanced through the end effector. Such unbalance can lead toundesirable friction between the firing member and the end effectorjaws. The creation of this additional friction may require anapplication of a higher firing force to overcome such friction as wellas can cause undesirable wear to portions of the jaws and/or the firingmember. An application of higher firing forces to the firing beam mayresult in unwanted flexure in the firing beam as it traverses thearticulation joint. Such additional flexure may cause the articulationjoint to de-articulate—particularly when the surgical end effector isarticulated at relatively high articulation angles. The surgicalinstrument 22010 employs a firing system 24300 that is identical to orvery similar in many aspects as firing system 2300 described above. Assuch, only those aspects of the firing system 24300 needed to understandthe operation of the surgical instrument 22010 will be discussed below.

As can be seen in FIGS. 50-54 , in at least one embodiment, the firingsystem 24300 comprises a firing member 24310 that includes avertically-extending firing member body 24312 that comprises a topfiring member feature 24320 and a bottom firing member feature 24350. Atissue cutting blade 24314 is attached to or formed in thevertically-extending firing member body 24312. See FIGS. 50 and 51 . Inat least one arrangement, it is desirable for the firing member 24310 topass through the anvil body 23212 with low friction, high strength andhigh stiffness. In the illustrated arrangement, the top firing memberfeature 24320 comprises a T-shaped body 24322 that has two laterallyextending tabs 24323 protruding therefrom and a top axial passage 24324extending therethrough. See FIG. 53 . The bottom firing member feature24350 comprises a T-shaped body 24352 that has two laterally extendingtabs 24353 protruding therefrom and a bottom axial passage 24354extending therethrough. See FIG. 50 . In at least one arrangement, thetop firing member feature 24320 and the bottom firing member feature24350 are integrally formed with the vertically-extending firing memberbody 24312. As can be seen in FIG. 54 , the anvil body 23212 comprisesan axially extending anvil slot 23240 that defines two opposed ledges23241 for slidably receiving the laterally extending tabs 24323 thereon.Similarly, the elongate channel 23110 comprises an axially extendingchannel slot 23140 that defines axially extending channel ledges 23141that are configured to slidably receive the laterally extending tabs24353 thereon.

In the illustrated arrangement, the firing system 24300 comprises anupper flexible spine assembly 24400 that is operably coupled to the topfiring member feature 24320 of the firing member 24310. In at least oneembodiment, the upper flexible spine assembly 24400 comprises an upperseries 24410 of upper vertebra members 24420 that are loosely coupledtogether by an upper flexible coupler member 24440 that extends througheach of the upper vertebra members 24420 and is attached to the topfiring member feature 24320.

As can be seen in FIG. 52 , each upper vertebra member 24420 issubstantially T-shaped when viewed from an end thereof. In one aspect,each upper vertebra member 24420 comprises an upper vertebra bodyportion 24422 that has a proximal end 24424 and a distal end 24428. Eachupper vertebra member 24420 further comprises a downwardly extendingupper drive feature or upper vertebra member tooth 24450 that protrudesfrom the upper vertebra body portion 24422. Each upper vertebra membertooth 24450 has a helix-shaped proximal upper face portion 24452 and ahelix-shaped distal upper face portion 24454. Each proximal end 24424 ofthe upper vertebra body portions 24422 has an arcuate or slightlyconcave curved shape and each distal end 24428 has an arcuate orslightly convex curved shape. When arranged in the upper series 24410,the convex distal end 24428 on one upper vertebra member 24420 contactsand mates with the concave proximal end 24424 on an adjacent uppervertebra member 24420 in the upper series 24410 to maintain the uppervertebra members 24420 roughly in alignment so that the helix-shapedproximal upper face portion 24452 and a helix-shaped distal upper faceportion 24454 on each respective upper vertebra member tooth 24450 canbe drivingly engaged by a rotary drive screw 2700 in the various mannersdisclosed herein. These curved mating surfaces on the upper vertebramembers 24420 allow the upper vertebras members 24420 to better transferloads between themselves even when they tilt.

In at least one embodiment, an upper alignment member 24480 is employedto assist with the alignment of the upper vertebra members 24420 in theupper series 24410. In one arrangement, the alignment member 24480comprises a spring member or metal cable which may be fabricated fromNitinol wire, spring steel, etc., and be formed with a distal upperlooped end 24482 and two upper leg portions 24484 that extend throughcorresponding upper passages 24425 in each upper vertebra body portion24422. The upper flexible coupler member 24440 extends through an upperpassage 24429 in each of the upper vertebra members 24420 to be attachedto the firing member 24310. In particular, a distal end portion 24442extends through the top axial passage 24324 in the top firing memberfeature 24320 and is secured therein by an upper retention lug 24444. Aproximal portion of the upper flexible coupler member 24440 mayinterface with a corresponding rotary spool or cable-management systemof the various types and designs disclosed herein that serve to payoutand take up the upper flexible coupler member 24440 to maintain adesired amount of tension therein during operation and articulation ofthe surgical end effector 23000. The cable management system may bemotor powered or manually powered (ratchet arrangement, etc.) tomaintain a desired amount of tension in the upper flexible couplermember 24440. The amount of tension in each flexible coupler member mayvary depending upon the relative positioning of the surgical endeffector 23000 to the elongate shaft assembly 24000.

The firing system 24300 further comprises a lower flexible spineassembly 24500 that is operably coupled to the bottom firing memberfeature 24350. The lower flexible spine assembly 24500 comprises a lowerseries 24510 of lower vertebra members 24520 that are loosely coupledtogether by a lower flexible coupler member 24540 that extends througheach of the lower vertebra members 24520 and is attached to the bottomfiring member feature 24350. As can be seen in FIG. 52 , each lowervertebra member 24520 is substantially T-shaped when viewed from an endthereof. In one aspect, each lower vertebra member 24520 comprises alower vertebra body portion 24522 that has a proximal end 24524 and adistal end 24528. Each lower vertebra member 24520 further comprises anupwardly extending lower drive feature or lower vertebra member tooth24550 that protrudes from the lower vertebra body portion 24522. Eachlower vertebra member tooth 24550 has a helix-shaped proximal lower faceportion 24552 and a helix-shaped distal lower face portion 24554. Theproximal end 24524 of each lower vertebra body portions 24522 has anarcuate or slightly concave curved shape and each distal end 24528 hasan arcuate or slightly convex curved shape. When arranged in the lowerseries 24510, the convex distal end 24528 on one lower vertebra member24520 contacts and mates with the concave proximal end 24524 on anadjacent lower vertebra member 24520 in the lower series 24510 tomaintain the lower vertebra members 24520 roughly in alignment so thatthe helix-shaped proximal lower face portion 24552 and a helix-shapeddistal lower face portion 24554 on each respective lower vertebra membertooth 24550 can be drivingly engaged by the rotary drive screw 2700 inthe various manners disclosed herein. These curved mating surfaces onthe lower vertebra members 24520 allow the lower vertebra members 24520to better transfer loads between themselves even when they tilt.

In at least one embodiment, a lower alignment member 24580 is employedto assist with the alignment of the lower vertebra members 24520 in thelower series 24510. In one arrangement, the lower alignment member 24580comprises a spring member or metal cable which may be fabricated fromNitinol wire, spring steel, etc., and be formed with a distal lowerlooped end 24582 and two lower leg portions 24584 that extend throughcorresponding lower passages 24525 in each lower vertebra body portion24522. The lower flexible coupler member 24540 extends through thebottom axial passage 24529 in each of the lower vertebra members 24520to be attached to the firing member 24310. In particular, a distal endportion 24542 of the lower flexible coupler member 24540 extends throughthe bottom axial passage 24354 in the bottom firing member feature 24350and is secured therein by a lower retention lug 24544. A proximalportion of the lower flexible coupler member 24540 may interface with acorresponding rotary spool or cable-management system of the varioustypes and designs disclosed herein that serve to payout and take up thelower flexible coupler member 24540 to maintain a desired amount oftension therein during operation and articulation of the surgical endeffector 23000. The cable management system may be motor powered ormanually powered (ratchet arrangement, etc.) to maintain a desiredamount of tension in the lower flexible coupler member 24540. The amountof tension in each flexible coupler member may vary depending upon therelative positioning of the surgical end effector 23000 to the elongateshaft assembly 24000.

In accordance with at least one aspect, a large surface area isadvantageous for distributing the force between the vertebra memberswhen they push so that the vertebra members cannot twist relative toeach other. The available area in the anvil and channel is limited andthe anvil and channel must remain stiff. The T-shaped upper vertebramembers 24420 and the T-shaped lower vertebra members 24520 are designedto fit in the limited spaces available in the anvil 23210 and theelongate channel 23110 while ensuring that there is a large amount ofarea to distribute the firing loads. The curved surfaces on each uppervertebra member 24420 and each lower vertebra member 24520 allow each ofthose vertebras to better transfer loads between themselves even whenthey tilt. The upper alignment member 24480 and the lower alignmentmember 24580 may also serve to prevent the upper vertebra members 24420and the lower vertebra members 24520 from twisting relative to eachother. The large surface area may also help to prevent galling of thevertebra members and/or the anvil and channel. The upper flexible spineassembly 24400 and the lower flexible spine assembly 24500 otherwiseoperably interface with the rotary drive screw 2700 arrangements asdisclosed herein. The upper flexible coupler member 24440 and the lowerflexible coupler member 24540 may also be used in the manners discussedabove to retract the firing member 24310 back to its starting positionif, during a firing stroke, the firing drive system 24300 fails.

As can be seen in FIG. 51 , the top firing member feature 24320 on thefiring member 24310 comprises a distal upper firing member tooth segment24330 that is equivalent to one half of an upper vertebra member tooth24450 on each upper vertebra member 24420. In addition, two proximalupper firing member teeth 24336 that are identical to an upper vertebramember tooth 24450 on each upper vertebra member 24420 are spaced fromthe distal upper firing member tooth segment 24330. The distal upperfiring member tooth segment 24330 and the proximal upper firing memberteeth 24336 may each be integrally formed with the top firing memberfeature 24320 of the firing member 24310. Likewise, the bottom firingmember feature 24350 of the firing member 24310 comprises a distal lowerfiring member tooth 24360 and two proximal lower firing member teeth24366 that are integrally formed on the bottom firing member feature24350. For example, in at least one arrangement, the firing member 24310with the rigidly attached teeth 24330, 24336, 24360, and 24366 may befabricated at one time as one unitary component using conventional metalinjection molding techniques. The person of ordinary skill in the artwill recognize that the firing member 24310 operates in essentially thesame manner as the firing member 2310 as was described in detail herein.

Turning now to FIGS. 55-58 , in accordance with at least one aspect, thearticulation joint 24200 comprises a movable exoskeleton assembly 24800.In one form, the movable exoskeleton assembly 24800 comprises a series24802 of movably interfacing annular rib members 24810. As can be seenin FIGS. 55-57 , each annular rib member 24810 comprises a first orproximal face 24820 that comprises a convex or domed portion 24822. Eachannular rib member 24810 further comprises a second or distal face 24830that is concave or dished. Each annular rib member 24810 furthercomprises an upper spine passage 24840 that is configured to accommodatepassage of the upper flexible spine assembly 24400 therethrough and alower spine passage 24842 that is configured to accommodate passage ofthe lower flexible spine assembly 24500 therethrough. In addition, eachannular rib member 24810 further comprises four articulation passages24850, 24852, 24854, and 24856 to accommodate passage of articulationactuators in the form of articulation cables 24242, 22446, 24250, and24254 therethrough. See FIG. 49 . Each annular rib member 24810 furthercomprises a central drive passage 24860 that is configured toaccommodate passage of the constant velocity (CV) drive shaft assembly2620 therethrough.

As can be seen in FIG. 58 , the movable exoskeleton assembly 24800comprises a proximal attachment rib 24870 that is configured to attachthe movable exoskeleton assembly 24800 to the distal end 24124 of theproximal support shaft 24120 by cap screws 24880 or other suitablefastener arrangements. The proximal attachment rib 24870 comprises afirst or distal face 24872 that is concave or dished to receive ormovably interface with the convex or domed portion 24822 of the proximalface 24820 of a proximal-most annular rib member 24810P. Similarly, themovable exoskeleton assembly 24800 comprises a distal attachment rib24890 that is configured to attach the movable exoskeleton assembly24800 to the proximal end 23112 of the elongate channel 23110 by capscrews 24882 or other suitable fasteners. The distal attachment rib24890 comprises a first or proximal face 24892 that comprises a convexor domed portion 24894 that configured to be received in or movablyinterface with the concave or dished distal face 24832 of a distal-mostannular rib member 24810D. In various embodiments, the annular ribmembers 24810, 24810P, and 24810D may be fabricated from any suitablemetal (e.g., stainless steel, titanium, etc.) or other suitablematerial. The annular rib members 24810, 24810P, and 24810D may beformed by suitable drawing or forming operations, by machining orcasting. The proximal faces 24820 and the distal faces 24830 may bepolished or otherwise finished to a desirable smooth finish to reducefriction and facilitate movement between the annular rib members 24810,24810P, and 24810D. In accordance with one aspect, all edges on eachannular rib member 24810, 24810P, 24810D are rounded to facilitaterelative movement between the annular rib members. The proximalattachment rib 24870 and the distal attachment rib 24890 may be formedwith similar attributes.

The surgical instrument 22010 also comprises an articulation system24240 that is configured to apply articulation motions to the surgicalend effector 23000 to articulate the surgical end effector 23000relative to the elongate shaft assembly 24000. In at least onearrangement, for example, as mentioned above, the articulation system24240 comprises four articulation cables 24242, 24246, 24250, and 24254that extend through the elongate shaft assembly 2400. See FIG. 49 . Inthe illustrated arrangement, the articulation cables 24242, 24246 passthrough the proximal attachment rib 24870 and through each of theannular rib members 24810P, 24810, and 24810D to be secured to thedistal attachment rib 24890. In one arrangement for example, each of thearticulation cables 24242, 24246 are secured to the distal attachmentrib 24890 by corresponding attachment lugs 24243. See FIGS. 61 and 63 .Likewise, the articulation cables 24250 and 24254 extend through theproximal attachment rib 24870 and through each of the annular ribmembers 24810P, 24810, and 24810D to be secured to the distal attachmentrib 24890 by corresponding attachment lugs 24243.

In one arrangement, each of the articulation cables 24242, 24246, 24250,and 24254 extend through corresponding coil springs 24896 that aresupported in cavities 24125 in the distal end 24124 of the rigidproximal support shaft 24120. In addition, each coil spring 24896 isassociated with a tensioning lug 24897 that is also journaled onto eachrespective articulation cable 24242, 24246, 24250, and 24524 and issecured thereon to attain a desired amount of compression in each spring24896 which serves to retain the annular rib members 24810P, 24810, and24810D in movable engagement with each other and with the proximalattachment rib 24870 and the distal attachment rib 24890. The cables24242, 24246, 24250, and 24254 operably interface with an articulationcontrol system that is supported in the housing of the surgicalinstrument 22010. For example, as was discussed above, a proximalportion of each cable 24242, 24246, 24250, and 24254 may be spooled on acorresponding rotary spool or cable-management system 2007 (FIG. 2 ) inthe housing portion of the surgical instrument 22010 that is configuredto payout and retract each cable 24242, 24246, 24250, and 24254 indesired manners. The spools/cable management system may be motor poweredor manually powered (ratchet arrangement, etc.). FIG. 59 illustrates thearticulation joint 24200 in an unarticulated position and FIG. 60illustrates the articulation joint in one articulated configuration.Such arrangement permits the surgical end effector 23000 to bearticulated through multiple articulation planes relative to theelongate shaft assembly 24000.

As can be seen in FIGS. 49, 58, and 64 , the surgical instrument 22010employs a constant velocity (CV) drive shaft assembly 2620 that spans orextends axially through the articulation joint 24200. The operation andconstruction of the CV drive shaft assembly 2620 was described in detailabove and will not be repeated here beyond what is necessary tounderstand the operation of the surgical instrument 22010. Briefly asdescribed above, the CV drive shaft assembly 2620 comprises a proximalCV drive assembly 2630 and a distal CV drive shaft 2670. The proximal CVdrive assembly 2630 comprises a proximal shaft segment 2632 thatconsists of an attachment shaft 2634 that is configured to benon-rotatably received within a similarly-shaped coupler cavity 2616 inthe distal end 2614 of the proximal rotary drive shaft 2610. Theproximal shaft segment 2632 operably interfaces with a series 2640 ofmovably coupled drive joints 2650. As can be seen in FIG. 58 as was alsodescribed previously, to ensure that the drive joints 2650 are engagedwith each other, a proximal drive spring 2740 is employed to apply anaxial biasing force to the series 2640 of drive joints 2650. Forexample, as can be seen in FIG. 58 , proximal drive spring 2740 ispositioned between the proximal mounting bushing 2734 and a supportflange that is formed between the distal socket portion 2636 and aproximal barrel portion 2638 of the proximal shaft segment 2632. In onearrangement, the proximal drive spring 2740 may comprise an elastomericO-ring received on the proximal barrel portion 2638 of the proximalshaft segment 2632. The proximal drive spring 2740 lightly biases thedrive joints 2650 together to decrease any gaps that occur duringarticulation. This ensures that the drive joints 2650 transfer loadstorsionally. It will be appreciated, however, that in at least onearrangement, the proximal drive spring 2740 does not apply a high enoughaxial load to cause firing loads to translate through the articulationjoint 2200.

To further prevent the drive joints 2650 from buckling duringarticulation, the series 2640 of movably coupled drive joints 2650extend through at least one low friction drive cover 24730 that extendsthrough the central drive passage 24860 in each of the annular ribmembers 24810. In the arrangement depicted in FIGS. 63 and 65 , thedrive cover 24730 comprises an outer and inner cut hypotube 24732. Suchhypotube 24732 may be fashioned from metal (e.g., stainless steel, etc.)and have multiple series of cuts or slits therein that may be made usinglaser cutter arrangements. In the illustrated arrangement, the hypotube24732 may be fabricated with an upper relief passage 24734 that providesclearance for the upper flexible spine assembly 24400 to pass thereoverduring operation while the surgical end effector 23000 is in anarticulated position and articulated positions. In addition, thehypotube 24732 may have a lower relief passage 24736 to provide similarclearance for the lower flexible spine assembly 24500. As can also beseen in FIG. 65 , the hypotube 24732 may be shaped with diametricallyopposed lateral tab portions 24738 to provide lateral stability duringarticulation. FIG. 66 illustrates an alternative drive cover 24730′ thatcomprises an inner cut hypotube 24732′. FIGS. 58, 67, 68 , and 69illustrate an alternative drive cover 24730″ that comprises flexibleheat shrink tubing 24732″ that is applied over the constant velocity(CV) drive shaft assembly 2620. In still other arrangements, the drivecover may comprise a coiled spring or coiled member as well.

Various embodiments of the present disclosure provide advantages overprevious surgical endocutter configurations that are capable ofarticulation. For example, pushing a firing member forward in anarticulating end effector generally requires a lot of force and thatforce must be balanced. For example, when firing the firing member at anangle of greater than sixty degrees, it becomes very difficult to push abeam through the articulation joint. The joint also experiencessignificant loads which may cause the articulation joint tode-articulate. By employing an upper flexible drive arrangement and alower flexible drive arrangement that are each flexible through thearticulation joint, but then become rigid when they are distal to thearticulation joint can allow for a large degree of articulation (e.g.,articulation angles over seventy degrees) while applying balanced loadsto the firing member that are constrained to the firing member and notto the articulation joint. Stated another way, torsional loads areapplied proximal to the articulation joint instead of longitudinal loadswhich could lead to de-articulation of the end effector. The torsionalloads are converted to longitudinal loads at a position that is distalto the articulation joint. Thus, the rotary drive screw serves toactually convert torsional motion or loads to longitudinal loads thatare applied to the firing member at a location that is distal to thearticulation joint.

Further, by longitudinally breaking up the threaded drive arrangements,the threaded drive arrangements pass through the articulation jointwhile also effectively decreasing the length of the surgical endeffector. For example, each single vertebra tooth is significantlyshorter than multiple pitches rigidly connected. The vertebra can angleas they pass through the articulation joint. This flexibleinterconnection enables the rotary drive screw to be closely positionedto the articulation joint as compared to being significantly spacedtherefrom if all of the pitches were rigidly connected.

FIGS. 70-73 illustrate another surgical end effector 4000 that may beemployed with a surgical instrument 3010 that may be similar to thesurgical instrument 10 in many aspects. The surgical end effector 4000may be similar to the surgical end effector 1000 except for thedifferences discussed below. The surgical end effector 4000 is operablycoupled to an elongate shaft assembly 5000. The elongate shaft assembly5000 may be operably attached to a housing portion of the surgicalinstrument 3010. The housing may comprise a handle that is configured tobe grasped, manipulated and actuated by the clinician. In otherembodiments, the housing may comprise a portion of a robotic system thathouses or otherwise operably supports at least one drive system that isconfigured to generate and apply at least one control motion which couldbe used to actuate the surgical end effectors disclosed herein and theirrespective equivalents.

In at least one form, the surgical end effector 4000 comprises a firstjaw 4100 and a second jaw 4200. In the illustrated arrangement, thefirst jaw 4100 comprises an elongate channel 4110 that comprises aproximal end 4112 and a distal end 4114 and is configured to operablysupport a surgical staple cartridge 1300 therein. In the illustratedarrangement, the second jaw 4200 comprises an anvil 4210 that may besimilar to anvil 1210 described above. In the illustrated arrangement,the elongate shaft assembly 5000 defines a shaft axis SA and comprises aproximal shaft segment that operably interfaces with a housing of thecontrol portion (e.g., handheld unit, robotic tool driver, etc.) of thesurgical instrument 3010. The elongate shaft assembly 5000 furthercomprises an articulation joint 5200 that is attached to a proximalshaft portion and the surgical end effector 4000.

The elongate shaft assembly 5000 may comprise a distal spine assembly5010 that is attached to the proximal end 4112 of the elongate channel4110 and the articulation joint 5200. See FIG. 70 . The distal spineassembly 5010 is non-movably supported in a distal outer tube segment5020 that operably interfaces with the surgical end effector 4000. Theelongate shaft assembly 5000 further includes a proximal spine member(not shown) that operably interfaces with a proximal end of thearticulation joint 5200 and may be attached to or otherwise operablyinterface with the housing of the surgical instrument 3010. A proximalouter tube segment 5030 extends from the articulation joint 5200 back tothe housing to operably interface therewith.

The surgical instrument 3010 employs a firing drive system 4300 thatcomprises a firing member 4310 that includes a vertically-extendingfiring member body 4312 that comprises a top firing member feature and abottom firing member feature. A tissue cutting blade 4314 is attached toor formed in the vertically-extending firing member body 4312. Thefiring drive system 4300 comprises a rotary drive nut 4400 that isconfigured to rotatably drive a series 4600 of drive components 4610that operably interface with the firing member 4310. The rotary drivenut 4400 comprises a flexible proximal segment 4410 that spans thearticulation joint 5200 and a threaded distal segment 4420 that isdistal to the articulation joint 5200. The threaded distal segment 4420comprises a series of variable pitched threads 4430, with coarse spacing4432 at the proximal end, and tighter spacing 4434 at the distal or exitend. See FIG. 72 . The threaded rotary drive nut 4400 comprises aproximal drive gear 4440 that meshingly interfaces with a distal drivegear 4510 that is attached to a rotary drive shaft 4500. See FIG. 70 .The rotary drive shaft 4500 may interface with a gearbox/motorarrangement supported in the housing of the surgical instrument 3010.Rotation of the rotary drive shaft 4500 causes the drive nut 4400 torotate about the shaft axis SA.

The rotary drive nut 4400 comprises a proximal segment 4410 and athreaded distal segment 4420. The threaded distal segment 4420 islocated distal to the articulation joint 5200 and is configured tothreadably engage a series 4600 of drive components 4610 that areloosely linked together by flexible tethers 4640. In at least onearrangement, for example, each drive component 4610 comprises avertically extending plate member 4612 that each includes a top end 4614and a bottom end 4618. The top end 4614 includes a top thread segment4616 and the bottom end 4418 includes a bottom thread segment 4620. Thetop thread segment 4616 and the bottom thread segment 4620 areconfigured to threadably engage the threads 4430 of the rotary drive nut4400. The series 4600 of drive components 4610 is configured to flexiblypass through the articulation joint 5200 and into a vertical passage5012 in the distal spine assembly 5010. Rotation of the rotary drive nut4400 in a first rotary direction causes the series 4600 of drivecomponents 4610 to move axially in the distal direction and rotation ofthe rotary drive nut 4400 in a second rotary direction will cause theseries 4600 of drive components 4610 to move axially in the proximaldirection.

Turning to FIG. 72 , in at least one arrangement, each drive component4610 further comprises a distally protruding latch feature 4630. Eachlatch feature 4360 is configured to be releasably received in latchingengagement within a latch cavity 4364 that is formed in the adjacentdrive component 4610 that is immediately distal thereto. When the drivecomponents 4610 are latched together, they form an axially rigid series4600AR of drive components for applying an axial drive motion to thefiring member 5310 to drive the firing member 5310 through the surgicalend effector 4000 from a starting to an ending position and then fromthe ending position back to the starting position. As can be seen inFIG. 72 , as the drive components 4610 enter the threaded distal segment4420 of the rotary drive nut 4400, they are loosely linked together. Asthe drive components 4610 threadably engage the finely pitched threads4430 in the threaded distal segment 4420 of the rotary drive nut 4400,the latch features 4630 are latchingly received within the correspondinglatch cavity 4364 in the distally adjacent drive component 4610 to formthe axially rigid series 4600AR of drive components 4610. In onearrangement, a distal-most drive component 4610 may be configured tolatchingly engage the firing member 4310 in a similar manner or inalternative arrangements, the distal-most drive component may benon-removably attached to the firing member 4310.

In the illustrated example, the drive components 4610 in the series 4600of drive components are flexibly linked together such that they can moverelative to each other to accommodate the articulation joint and withoutthe need for reinforcing and support plates that are commonly requiredwhen pushing a firing beam through an articulated joint. As the seriesof drive components 4610 enters and is drivingly engaged by the threadeddistal segment 4420 which is distal to the articulation joint, the drivecomponents 4610 form the axially rigid series of drive components fordriving the firing member 4310 through the surgical end effector 4000.The anvil 4210 may be pivoted into an open position by a spring or otherarrangement in the various manners disclosed herein and then closed bythe firing member 4310 as the firing member 4310 is driven distally froma starting position to an ending position in the various mannersdiscussed herein. Other jaw control arrangements may also be employed tocontrol the opening and closing of the jaws.

FIGS. 73-76 illustrate another surgical end effector 6000 that employs adrive system 6300 that comprises a series 6600 of flexibly linked drivecomponents 6610 that can be used to traverse an articulation joint 6200and rigidly advance a firing member 6130 through the surgical endeffector 6000. The surgical end effector 6000 may comprise a channel6010 that is configured to operably support a surgical staple cartridge(not shown) therein. An anvil 6020 may be pivotally coupled to thechannel 6010 and is movable between an open position and a closedposition by the firing member 6130 or other closure system arrangement.The anvil 6020 may be moved to an open position by a spring or otherarrangement in the various manners disclosed herein.

Turning to FIG. 74 , in at least one arrangement, each drive component6610 comprises a drive component body 6612 that has a proximal face6614, a distal face 6616, and thread segment 6620 that is formed on abottom surface 6618. Each drive component 6610 further comprises aproximally protruding latch feature 6630. Each latch feature 6630comprises a neck feature 6632 that has a spherical latch head 6634formed on an end thereof. The latch feature 6630 is configured to bemovably received within a latch cavity 6336 that is formed in theadjacent drive component 6610 that is immediately distal thereto. Tofacilitate movable attachment of the drive components 6610 in movableserial arrangement, the spherical latch head 6634 is inserted through atapered passage 6338 in the drive component body 6612 and into the latchcavity 6636. The spherical latch head 6634 is sized and shaped relativeto the latch cavity 6636 to permit relative movement between the drivecomponents 6610 when arranged as shown in FIG. 74 . However, when thedrive components are axially aligned such that the distal face 6616 ofone drive component 6610 is in abutting engagement with the proximalface 6614 of the drive component that is immediately distal thereto, thedrive components 6610 form an axially rigid series 6600AR of drivecomponents that can drive the firing member 6130 through the surgicalend effector 6000.

As can be seen in FIG. 73 , a flexible rotary drive system 6700 isemployed to drive the series of 6600 drive components 6610. In onearrangement, the flexible rotary drive system 6700 comprises a flexiblerotary drive shaft 6710 that can pass through the articulation joint6210 and includes a rotary drive gear 6720 that is configured tothreadably engage the thread segments 6620 on each drive component 6610.The flexible rotary drive shaft 6710 may be rotated by a motor/geararrangement supported in a housing of a surgical instrument. The portion6600F of the series 6600 of drive components 6610 that is proximal tothe rotary drive gear 6720, remains flexibly linked or “floppy”. As thedrive components 6610 are threadably engaged by the rotary drive gear6720 they are driven through a passage in the channel 6010 that causesthe drive components to form the axially rigid series 6600AR for drivingthe firing member 6130 through the surgical end effector 6000.

Torsional loads that are applied to firing system components as theytraverse the articulation joint are less likely to de-articulate thearticulation joint than axial loads. Various embodiments disclosedherein transfer torsional loads to longitudinal loads in a location thatis distal of the articulation joint. Because the longitudinal loads arecontained in the end effector, de-articulation is prevented. FIG. 77illustrates one firing system 6800 example that can provide suchadvantages. The firing system 6800 comprises a firing member 6810 thatis configured to be operably supported in a surgical end effector in thevarious manners described herein. A flexible spring-like driven member6820 is attached to the firing member 6810. Such flexible, spring-likedriven member 6820 can span an articulation joint area 6840 that canattain relatively large ranges of articulation. The flexible,spring-like driven member 6820 is configured to be driven axially by aflexible, spring-like torsion drive member 6830 that is rotatablysupported to span the articulation joint area 6840. The flexible,spring-like torsion drive member 6830 includes a threaded insert 6832that is configured to threadably engage the spring-like driven member6820 at a location 6841 that is distal to the articulation joint area6840. The flexible, spring-like torsion drive member 6830 may be rotatedby a motor/gear arrangement supported in a housing of a surgicalinstrument. As the flexible, spring-like torsion drive member 6830rotates in a first direction, the flexible, spring-like driven member6820 translates longitudinally to drive the firing member 6810. Rotationof the flexible torsion drive member 6830 in a second direction willcause the flexible, spring-like driven member to move proximally.

FIG. 78 illustrates another firing system 6850 that comprises a firingmember 6860 that is configured to be operably supported in a surgicalend effector in the various manners described herein. The firing member6860 is driven by firing member drive assembly 6861 which comprises aseries 6862 of spherical ball members 6870 that are coupled together bya flexible cable 6872. Such series 6862 of flexible spherical ballmembers 6870 can span an articulation joint area 6840 that can attainrelatively large ranges of articulation. The series 6862 of flexiblespherical ball members 6870 is configured to be driven axially by aflexible torsion drive member 6880 that is rotatably supported to spanan articulation joint area 6890. The flexible torsion drive member 6880includes an insert 6882 that is configured to drivingly engage thespherical ball members 6870 at a location 6892 that is distal to thearticulation joint area 6890. The flexible torsion drive member 6880 maybe rotated by a motor/gear arrangement supported in a housing of asurgical instrument. As the flexible torsion drive member 6880 rotatesin a first direction, the spherical ball members 6870 are drivendistally into contact with each other to form an axially rigid series6862AR that translates longitudinally to drive the firing member 6860distally. Rotation of the flexible torsion drive member 6880 in a seconddirection will cause the series of spherical ball members 6870 to moveproximally.

FIG. 79 illustrates another firing system 6950 that comprises a firingmember 6960 that is configured to be operably supported in a surgicalend effector in the various manners described herein. A laser cut,hypotube driven member 6970 is attached to the firing member 6960. Suchflexible driven member 6970 can span an articulation joint area 6940that can attain relatively large ranges of articulation. The flexibledriven member 6970 is configured to be driven axially by a flexibletorsion drive member 6980 that is rotatably supported to span thearticulation joint area 6940. The flexible torsion drive member 6980includes a threaded insert 6982 that is configured to threadably engagethe laser cuts 6972 on the flexible driven member 6970 at a location6942 that is distal to the articulation joint area 6940. The flexibletorsion drive member 6980 may be rotated by a motor/gear arrangementsupported in a housing of a surgical instrument. As the flexible torsiondrive member 6980 rotates in a first direction, the flexible drivenmember 6970 translates longitudinally to drive the firing member 6960.Rotation of the flexible torsion drive member 6980 in a second directionwill cause the flexible driven member 6970 to move proximally.

Pushing a firing beam forward in an articulating end effector generallyrequires a lot of force and such force needs to be balanced. Forexample, it is generally difficult to push a firing beam through anarticulation joint that has been articulated to angles of greater thansixty degrees. As the firing beam traverses through the articulationjoint, the firing beam can apply significant loads onto the articulationjoint components which can cause the articulation joint tode-articulate. FIGS. 80-84 illustrate a firing drive system 7300 thatcomprises a flexible upper drive band 7320 and a flexible lower driveband 7330 that are attached to a firing member 7310 that is configuredto move within a surgical end effector 7000 between a starting andending position. As can be seen in FIGS. 80-82 , the flexible upperdrive band 7320 comprises a plurality of spaced upper drive teeth 7322that are configured to threadably engage a helical thread 7342 on arotary drive nut 7340. Similarly, the flexible lower drive band 7330comprises a plurality of spaced lower drive teeth 7332 that areconfigured to threadably engage the helical thread 7342 on the rotarydrive nut 7340. In at least one arrangement, the flexible upper driveband 7320 and the flexible lower drive band 7330 are formed from a metalmaterial and are welded to or otherwise attached to the firing member7310. Such arrangement serves to balance the firing loads that areapplied to the firing member 7310.

The rotary drive nut 7340 is received on a flexible rotary drive shaft7350 that is centrally disposed between the flexible upper drive band7320 and the flexible lower drive band 7330 and traverses through thearticulation joint area generally designated as 7200. The flexiblerotary drive shaft 7350 may be rotated by a motor/gear arrangementsupported in a housing of a surgical instrument. As the flexible rotarydrive shaft 7350 rotates in a first direction, the flexible upper driveband 7320 and the flexible lower drive band 7330 will drive the firingmember 7310 distally. Rotation of the flexible rotary drive shaft 7350in a second direction will cause the flexible upper drive band 7320 andthe flexible lower drive band 7330 to pull the firing member 7310proximally. In at least one arrangement, flexible upper drive band 7320and the flexible lower drive band 7330 pass through a guide member 7360that surrounds the rotary drive nut 7340 to prevent the flexible upperdrive band 7320 and the flexible lower drive band 7330 from bypassingthe rotary drive nut 7340 during actuation of the flexible rotary driveshaft 7350. See FIG. 84 .

In the illustrated arrangement, the firing member 7310 is configured tomove through the surgical end effector 7000 that comprises a first jaw7010 and a second jaw 7030 that is configured to move relative to thefirst jaw 7010. In one embodiment, the first jaw 7010 comprises anelongate channel 7012 that is configured to operably support a surgicalstaple cartridge therein. See FIGS. 80 and 81 . The second jaw 7030comprises an anvil 7032 that is pivotally supported on the elongatechannel 7012 and is movable between an open position and a closedposition relative to the elongate channel 7012. As can be seen in FIG.82 , in at least one form, the firing member 7310 comprises a shape thatis commonly referred to as an “E-beam”. The firing member 7310 comprisesa vertically extending firing member body 7312 that has a lower footfeature 7314 that comprises two laterally extending tabs 7315 that areconfigured to be slidably engage the elongate channel 7012 as the firingmember is driven axially therein. In addition, a pair of upper tabs 7316protrude from the upper portion of the firing member body 7312 to engagethe anvil 7032 as the firing member 7310 is driven distally through theclosed anvil 7032. During the firing stroke, the tabs 7315 and 7316 mayserve to space the anvil 7032 relative to the surgical staple cartridgesupported in the elongate channel 7012. The firing member body 7312 alsocomprises a tissue cutting feature 7318. The tabs 7316 may also serve toapply a closing motion to the anvil 7032 as the firing member 7310 ismoved distally from the starting position.

In the illustrated example, the firing drive system 7300 may also beemployed to apply opening and closing motions to the anvil 7032. As canbe seen in FIGS. 80-83 , a closure nut 7370 is threadably received onthe flexible rotary drive shaft 7350. The closure nut 7370 comprises acam pin 7372 that extends laterally from each side of the closure nut7370 to be received in corresponding cam slots 7036 in an anvil mountingportion 7034 of the anvil 7032. See FIGS. 80 and 81 . Such cam pins 7372prevent the closure nut 7370 from rotating with the flexible rotarydrive shaft 7350 such that rotation of the flexible rotary drive shaft7350 causes the closure nut 7370 to move axially. Thus, rotation of theflexible rotary drive shaft 7350 in a first direction causes the closurenut 7370 to move distally and cam the anvil 7032 from the open positionto the closed position. Rotation of the flexible rotary drive shaft 7350in the second rotary direction will cause the closure nut 7370 to moveproximally and cam the anvil 7032 back to the open position. Thus,alternating the rotation of the flexible rotary drive shaft 7350 mayallow the surgeon to quickly open and close the anvil 7032 for graspingpurposes, for example.

FIG. 85 illustrates an alternative firing drive assembly 7302 thatcomprises the flexible upper drive band 7320′ that has upper drive teeth7322′ and a flexible lower drive band 7330′ that has lower drive teeth7332′ that is formed out of one piece of material such as metal. Theflexible upper drive band 7320′ also includes upper strength tabs 7324′that are provided to pass through the anvil 7032 similar to the uppertabs 7316 on the firing member 7310 as well as lower strength tabs 7334that are provided to pass through the channel 7012 similar to the tabs7315 on the firing member 7310. FIG. 86 illustrates an alternativefiring drive assembly 7302′ that is fabricated from two band assemblies7302A and 7302B that are laminated together to form the flexible upperdrive band 7320″ that has the upper drive teeth 7322″ and a flexiblelower drive band 7330″ that has the lower drive teeth 7332″. Each bandassembly 7302A, 7302B also comprise upper strength tabs 7324A″, 7324B″and lower strength tabs 7334A″, 7334B″ that are provided to pass throughthe anvil 7032 and the elongate channel 7012, respectively.

The firing drive system 7300 serves to apply a uniform drive motion tothe firing member 7310 and can accommodate articulation angles that maybe greater than seventy degrees, for example. In addition, because therotary drive nut 7340 engages the flexible upper drive band 7320 andflexible lower drive band 7330 at a location that is distal to thearticulation joint area 7200, the linear firing loads are confined tothe end effector and do not go through the articulation joint.

FIGS. 87-89 illustrate another form of surgical instrument 9010 that mayaddress many of the challenges facing surgical instruments with endeffectors that are articulatable to large articulation angles and thatare configured to cut and fasten tissue. In various embodiments, thesurgical instrument 9010 may comprise a handheld device. In otherembodiments, the surgical instrument 9010 may comprise an automatedsystem sometimes referred to as a robotically-controlled system, forexample. In various forms, the surgical instrument 9010 comprises asurgical end effector 10000 that is operably coupled to an elongateshaft assembly 12000. The elongate shaft assembly 12000 may be operablyattached to a housing. In one embodiment, the housing may comprise ahandle that is configured to be grasped, manipulated and actuated by theclinician. In other embodiments, the housing may comprise a portion of arobotic system that houses or otherwise operably supports at least onedrive system that is configured to generate and apply at least onecontrol motion which could be used to actuate the surgical end effectorsdisclosed herein and their respective equivalents. In addition, variouscomponents may be “housed” or contained in the housing or variouscomponents may be “associated with” a housing. In such instances, thecomponents may not be contained with the housing or supported directlyby the housing. For example, the surgical instruments disclosed hereinmay be employed with various robotic systems, instruments, componentsand methods disclosed in U.S. Pat. No. 9,072,535, entitled SURGICALSTAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS,which is incorporated by reference herein in its entirety.

In one form, the surgical end effector 10000 comprises a first jaw 10100and a second jaw 10200. In the illustrated arrangement, the first jaw10100 comprises an elongate channel 10110 that comprises a proximal end10112 and a distal end 10114 and is configured to operably support asurgical staple cartridge 10300 therein. The surgical staple cartridge10300 comprises a cartridge body 10302 that has an elongate slot 10304therein. A plurality of surgical staples or fasteners (not shown) arestored therein on drivers (not shown) that are arranged in rows on eachside of the elongate slot 10304. The drivers are each associated withcorresponding staple cavities 10308 that open through a cartridge decksurface 10306. The surgical staple cartridge 10300 may be replaced afterthe staples/fasteners have been discharged therefrom. Other embodimentsare contemplated wherein the elongate channel 10110 and/or the entiresurgical end effector 10000 is discarded after the surgical staplecartridge 10300 has been used.

In the illustrated arrangement, the second jaw 10200 comprises an anvil10210 that comprises an elongate anvil body 10212 that has a proximalend 10214 and a distal end 10216. The anvil body 10212 comprises astaple-forming undersurface 10218 that faces the first jaw 10100 and mayinclude a series of staple-forming pockets (not shown) that correspondto each of the staples or fasteners in the surgical staple cartridge10300. The anvil body 10212 may further include a pair of downwardlyextending tissue stop features 10220 that are formed adjacent theproximal end 10214 of the anvil body 10212. One tissue stop feature10220 extends from each side of the anvil body 10212 such that a distalend 10222 on each tissue stop 10220 corresponds to the proximal-moststaples/fasteners in the surgical staple cartridge 10300. When the anvil10200 is moved to a closed position onto tissue positioned between thestaple-forming undersurface 10218 of the anvil 10200 and the cartridgedeck surface 10306 of the surgical staple cartridge 10300, the tissuecontacts the distal ends 10222 of the tissue stops 10220 to prevent thetissue from migrating proximally past the proximal-moststaples/fasteners to thereby ensure that the tissue that is cut is alsostapled. When the surgical staple cartridge is “fired” as will bediscussed in further detail below, the staples/fasteners supportedwithin each staple cavity are driven out of the staple cavity 10308through the clamped tissue and into forming contact with the stapleforming undersurface 10218 of the anvil 10200.

As can be seen in FIG. 88 , the proximal end 10214 of the anvil body10212 comprises an anvil mounting portion 10230 that comprises a pair oflaterally extending mounting pins 10232 that are configured to bereceived in corresponding mounting inserts 10130 that are configured tobe retainingly received within mounting cradles 10120 formed in theproximal end 10112 of the elongate channel 10110. The mounting pins10232 are pivotally received within pivot holes 10132 in the mountinginserts 10130 and then the mounting inserts 10130 are inserted intotheir corresponding cradle 10120 and affixed to the elongate channel10110 by welding, adhesive, snap fit, etc. Such arrangement facilitatespivotal travel of the anvil 10210 relative to the elongate channel 10110about a fixed (i.e., non-translating, non-moving) pivot axis PA. SeeFIG. 87 .

In the illustrated arrangement, the elongate shaft assembly 12000defines a shaft axis SA and comprises a hollow outer tube (omitted forclarity) that operably interfaces with a housing of the control portion(e.g., handheld unit, robotic tool driver, etc.) of the surgicalinstrument 9010. The elongate shaft assembly 12000 further comprises anarticulation joint 12200 that may be attached to the hollow outer tubeas well as the surgical end effector 10000 to facilitate selectivearticulation of the surgical end effector 10000 relative to the elongateshaft assembly 12000 about multiple articulation axes in multiplearticulation planes. In at least one arrangement, for example, thearticulation joint 12200 comprises a proximal joint member 12210, acentral joint member 12230, and a distal joint member 12250. In oneexample, the central joint member 12230 operably interfaces with theproximal joint member 12210 such that the central joint member 12230 isselectively articulatable through a first or proximal articulation planethat is defined by a first or proximal articulation axis AA₁ that istransverse to the shaft axis SA. Also in one example, the distal jointmember 12250 operably interfaces with the central joint member 12230such that the distal joint member 12250 is selectively articulatablethrough a second or distal articulation plane that is defined by asecond or distal articulation axis AA₂ that is transverse to the shaftaxis SA and transverse to the first or proximal articulation axis AA₁.

As can be seen in FIGS. 89 and 90 , the proximal joint member 12210comprises a proximal joint distal face 12212 that defines two spaced,lateral apex portions 12214, 12216. The apex portion 12214 defines aradial surface 12215 and the apex portion 12216 defines a radial surface12217 (FIG. 90 ). The central joint member 12230 comprises proximal face12232 that defines two spaced lateral proximal apex portions 12234,12236. The proximal apex portion 12234 defines a radial surface 12235and the apex portion 12236 defines a radial surface 12237. As can beseen in FIG. 89 , the proximal face 12232 of the central joint member12230 confronts the proximal joint distal face 12212 of the proximaljoint member 12210 such that the central joint member 12230 isarticulatable through a first articulation plane defined by the first orproximal articulation axis AA₁ that extends between a point where thelateral apex portion 12214 on the proximal joint member contacts theproximal apex portion 12234 on the central joint member 12230 and thepoint where the lateral apex portion 12216 on the proximal joint member12210 contacts the proximal apex portion 12236 on the central jointmember 12230. In one arrangement, the radial surfaces 12215, 12217 onthe lateral apex portions 12214, 12216, respectively, and the radialsurfaces 12235 and 12237 on the proximal apex portions 12234, 12236,respectively, may act as rocker points/surfaces about which the centraljoint member 12230 may articulate relative to the proximal joint member12210. Additionally, the central joint member 12230 comprises proximalfirst gear tooth segments that are configured to rotatably mesh withdistal gear segments 12218, 12220 on the proximal joint member 12210.See FIG. 88 . In various arrangements, the radial surface 12235 on thecentral joint member 12230 may be spaced from the radial surface 12215on the proximal joint member 12210 and the radial surface 12237 on thecentral joint member 12230 may be spaced from the radial surface 12217on the proximal joint member 12210.

The central joint member 12230 further comprises a central joint distalface 12240 that defines a centrally disposed upper apex portion 12242that forms an upper radial surface 12244 and a lower apex portion 12246that forms a lower radial surface 12248. See FIG. 89 . The distal jointmember 12250 is attached to the proximal end 10112 of the elongatechannel 10110 by a mounting bushing 10150 and comprises a proximal face12251 that faces or confronts the central joint distal face 12240 on thecentral joint member 12230. See FIGS. 89 and 92 . As can be seen inFIGS. 89 and 92 , the proximal face 12251 defines a centrally disposedupper apex portion 12252 that forms an upper radial surface 12254 thatis configured to confront or abut the upper radial surface 12244 on thecentral joint member 12230. The proximal face 12251 further defines acentrally disposed lower apex portion 12256 that forms a lower radialsurface 12258 that is configured to confront or abut the lower radialsurface 12248 on the central joint member 12230. See FIG. 89 . Thedistal joint member 12250 further comprises an upper gear tooth segment12253 that is configured to rotatably mesh with an upper gear toothsegment 12243 on the central joint member 12230. In addition, the distaljoint member 12250 comprises a lower gear tooth segment 12255 that isconfigured to rotatably mesh with a lower gear tooth segment 12245 onthe central joint member 12230. See FIG. 92 .

The distal joint member 12250 is configured to articulate through asecond or distal articulation plane defined by the second or distalarticulation axis AA₂ that extends between a point where the upper apexportion 12252 on the distal joint member 12250 contacts or confronts theupper apex portion 12242 on the central joint member 12230 and the pointwhere the lower apex portion 12256 on the distal joint member 12250contacts or confronts the lower apex portion 12246 on the central jointmember 12230. See FIGS. 89 and 92 . In one arrangement, the radialsurfaces 12254, 12258 on the upper and lower apex portions 12252, 12256,respectively of the distal joint member 12250 and the radial surfaces12244 and 12248 on the upper and lower apex portions 12242, 12246,respectively on the central joint member 12230 may act as rockerpoints/surfaces about which the distal joint member 12250 may articulaterelative to the central joint member 12230. In alternative arrangements,however, the radial surface 12254 on the distal joint member 12250 isspaced from the radial surface 12244 on the central joint member 12230and the radial surface 12258 on the distal joint member 12250 is spacedfrom the radial surface 12248 on the central joint member 12230.

Returning to FIG. 88 , in the illustrated example, the articulationjoint 12200 is operably controlled by a cable control system 9030 thatcomprises four cables 12510, 12520, 12530, and 12540 that extend throughthe elongate shaft assembly 12000. The cable control system 9030 may besupported within a housing 9020 of the surgical instrument 9010. Thecable control system 9030 may comprise a plurality of cable supportmembers/capstans, pulleys, etc. that are controlled by one or morecorresponding motors that are controlled by a control circuit portion ofthe surgical instrument 9010. In various embodiments, the cable controlsystem 9030 is configured to manage the tensioning (pulling) and payingout of cables at precise times during the articulation process. Inaddition, in at least one arrangement, the cable control system 9030 isemployed to control the opening and closing of the anvil 10210 as willbe discussed in further detail below.

As can be seen in FIG. 88 , the cables 12510, 12520, 12530, and 12540are configured to operably interface with a closure system 12600 that isrotatably mounted in the proximal end 10112 of the elongate channel10110. In at least one arrangement, the closure system 12600 comprises apulley unit 12610 that comprises a first lateral alpha wrap pulley 12620and a second lateral alpha wrap pulley 12630 that are interconnected bya central shaft 12640. See FIGS. 93 and 94 . The pulley unit 12610 isrotatably supported within the proximal end 10112 of the elongatechannel 10110 by mounting brackets 12710 and 12720. See FIG. 88 . Moreparticularly, the proximal end 10112 of the elongate channel 10110defines a firing member parking area 10140 that is proximal to themounting cradles 10120 and is configured to operably support a firingmember 12310 when in a starting position. Each mounting bracket 12710,12720 is mounted within the firing member parking area 10140 on eachside of the shaft axis SA to enable the firing member 12310 to bereceived in the parking area 10140 when the firing member 12310 is in astarting position. The mounting brackets 12710, 12720 may be attached tothe proximal end 10112 of the elongate channel 10110 by welding,adhesive, snap features, etc. The mounting bracket 12710 comprises afirst shaft cradle 12712 that is configured to rotatably support a firstpivot shaft 12621 protruding from the first lateral alpha wrap pulley12620 and the second mounting bracket 12720 comprises a second shaftcradle 12722 that is configured to rotatably support a second pivotshaft 12644 protruding from the second lateral alpha wrap pulley 12630.In addition, each mounting bracket 12710, 12720 further includes arelief area 12732 that is shaped to receive the corresponding first andsecond alpha wrap pulleys 12620, 12630 therein.

As can be seen in FIG. 94 , the first alpha wrap pulley 12620 comprisesa first circumferential groove 12622 and a second circumferential groove12624. In the illustrated example, the first cable 12510 is received inthe first circumferential groove 12622 and is attached thereto and thesecond cable 12520 is received in the second circumferential groove12624 and is attached thereto. Pulling on the first cable 12510 willresult in the rotation of the first lateral alpha wrap pulley 12620 in afirst direction and pulling the second cable 12520 will result in therotation of the first lateral alpha wrap pulley 12620 in a secondopposite direction. Similarly, the second lateral alpha wrap pulley12630 comprises a first circumferential groove 12632 and a secondcircumferential groove 12634. In the illustrated arrangement, cable12540 is received in the first circumferential groove 12632 and isattached thereto and the second cable 12520 is received in the secondcircumferential groove 12634 and is attached thereto. Pulling on thefourth cable 12540 will result in the rotation of the first second alphawrap pulley 12630 in the first direction and pulling the third cable12530 will result in the rotation of the second lateral alpha wrappulley 12630 in the second opposite direction. The lateral alpha wrappulleys 12620, 12630 can rotate approximately three hundred thirtydegrees. This range of rotational travel is in contrast to a normalpulley that may have a range of rotational travel that is less than onehundred eighty degrees of rotation.

Each of the first and second lateral alpha wrap pulleys 12620, 12630also comprises a corresponding spiral closure cam that is configured toapply closure motions to the anvil 10210. As can be seen in FIG. 94 ,the first lateral alpha wrap pulley 12620 includes a first spiralclosure cam 12626 and the second lateral alpha wrap pulley 12630 has asecond spiral closure cam 12636 thereon. The spiral closure cams 12626,12636 are configured to cammingly interact with corresponding anvilclosure arms 10234 on the anvil mounting portion 10230 of the anvil10210 to apply closure motions thereto. FIG. 96 illustrates the positionof a spiral closure cam 12626 on the first lateral alpha wrap pulley12620 when the anvil 10210 is biased into the open position by an anvilspring 10240. Rotation of the pulley unit 12610 in a first rotarydirection will cause the spiral closure cams 12626 to cam the anvil 1210to the closed position shown in FIG. 97 . To open the anvil 10210, thepulley unit 12610 is rotated in opposite direction back to the positionshown in FIG. 96 .

Referring now to FIGS. 91 and 93 , the first cable 12510 extends fromthe cable control system through the elongate shaft assembly and througha passage in the proximal joint member 12210 and is looped around tworedirect pulleys 12650, 12660 that are supported on shafts 12602, 12612that are mounted in the central joint member 12230. The first cable12510 exits the central joint member 12230 through passage 12231 andextends through passage 12257 in the distal joint member 12250 to bereceived within the first circumferential groove 12622 in the firstlateral alpha wrap pulley 12620 where it is attached thereto. A secondcable 12520 extends from the cable control system through the elongateshaft assembly and through passage 12213 in the proximal joint member12210 to be looped around the redirect pulleys 12650, 12660 in thecentral joint member 12230. The second cable 12520 exits the centraljoint member 12230 through a corresponding passage 12241 and extendsthrough passage 12259 in the distal joint member 12250 to be receivedwithin the second circumferential groove 12624 in the first lateralalpha wrap pulley 12620 where it is attached thereto.

In the illustrated example, the third cable 12530 extends from the cablecontrol system 9030 through the elongate shaft assembly 12000 andthrough a corresponding passages in the proximal joint member 12210, thecentral joint member 12230, and the distal joint member 12250 to bereceived within a corresponding circumferential groove in the secondlateral alpha wrap pulley 12630 where it is attached thereto. Inaddition, a fourth cable 12540 extends from the cable control system9030 through the elongate shaft assembly 12000 and through correspondingpassages in the proximal joint member 12210, the central joint member12230, and the distal joint member 12250 to be received within acorresponding circumferential groove in the second lateral alpha wrappulley 12630 where it is attached thereto.

In at least one example, to articulate the surgical end effector 10000relative to the elongate shaft assembly 12000 through a firstarticulation plane that is defined by the first articulation axis AA₁,the cable control system 9030 is actuated to pull on the second cable12520 and the fourth cable 12540 simultaneously with a same amount oftension being applied to each cable 12520 and 12540. Because the cables12520, 12540 apply equal amounts of tension on both sides of the pulleyunit 12610, the pulley unit 12610 does not rotate. However, the pullingaction of the cables 12520 and 12540 is translated through thearticulation joint 12200 to the surgical end effector 10000 whichresults in the articulation of the central joint member 12230 relativeto the proximal joint member 12210 about the first articulation axisAA₁. See FIGS. 92 and 98 . To articulate the surgical end effector 10000through a second plane of articulation that is defined by the secondarticulation axis AA₂ and is transverse to the first plane ofarticulation, the cable control system 9030 is actuated to pull thethird cable 12530 and the fourth cable 12540 simultaneously with a sameamount of tension being applied to each cable 12530 and 12540. Becausethe cables 12530, 12540 apply equal amounts of tension on both sides ofthe second lateral alpha wrap pulley 12630 of the pulley unit 12610, thepulley unit 12610 does not rotate. However, the pulling action of thecables 12530 and 12540 is translated through the articulation joint12200 to the surgical end effector 10000 which results in thearticulation of the distal joint member 12250 relative to the centraljoint member 12230 about the second articulation axis AA₂. See FIGS. 92and 99 .

The cable control system 9030 may also be used to control the openingand closing of the anvil 10210 in the following manner. As indicatedabove, when the spiral cams 10626 on the first lateral alpha wrap pulley10620 and the second lateral alpha wrap pulley 10630 are in the positionshown in FIG. 96 , the anvil 10210 is biased into the open position bythe anvil spring 10240. To close the anvil 10210 from that position, thecable control system 9030 is actuated to pull the first cable 12510 andthe fourth cable 12540 simultaneously with a same amount of tensionbeing applied to each cable 12510 and 12540. These cables 12510 and12540 will cause the pulley unit 12610 to rotate into the closureposition shown in FIG. 97 which causes the closure cams 10626 tocammingly contact the anvil closure arms 10234 to pivot the anvil 10210into the closed position. It will be appreciated that by applying equalamounts of tension into the cables 12510 and 12540, no moment is appliedto the central joint member 12230 and/or distal joint member 12250because there are equal amounts of tension being applied on each side ofthe articulation joint 12200. See FIG. 91 . Such arrangement allows thejaw closure to be profiled as desired. This cable-controlled system 9030allows for a faster closure when the anvil is fully open. Thecable-controlled system 9030 can also function as a lower speed/higherforce generating closure mechanism for clamping onto tissue. The presentcable controlled system 9030 may also not produce the backlash thatcommonly occurs with other cable-controlled systems and thus can also beused to control the articulation position of the end effector. As willbe further discussed below, this cable actuated closure and articulationsystem does not cross across the center axis or shaft axis of thearticulation joint which provides critical space for a firing drivesystem 13000.

The above-described articulation joint 12200 and cable controlled system9030 can facilitate two plane articulation while also supplying anadditional actuation motion to the surgical end effector 10000 whilekeeping the central area of the articulation joint 12200 free for othercontrol systems as will be discussed in further detail below. Thearticulation joint 12200 uses the last degree of freedom to actuate thejaw closure of the surgical end effector. In one aspect, thearticulation joint 12200 comprises an N+1 joint, meaning that for Ndegrees of freedom, the joint requires N+1 cables to actuate it. Thus,in the above-described example, the articulation joint 12200 employsfour actuation cables.

As can be seen in FIGS. 100-103 , the firing drive system 13000comprises a firing member 13310 that includes a vertically-extendingfiring member body 13312 that has two laterally extending tabs 13314protruding from a bottom portion 13313 of the firing member body 13312.The tabs 13314 are configured to be slidably engage ledges 10113 in theelongate channel 10110 as the firing member 13310 is driven axiallytherein. In addition, a pair of upper tabs 13316 protrudes from a topportion 13315 of the firing member body 13312. The upper tabs 13316 areconfigured to engage ledges 10213 (FIG. 103 ) in the anvil body 10212 asthe firing member 13310 is driven distally through the closed anvil10210. During the firing stroke, the tabs 13314 and 13316 may serve tospace the anvil 10210 relative to a surgical staple cartridge that issupported in the elongate channel 10110. The firing member body 13312also comprises a tissue cutting feature 13318 and a proximally-facingnotch 13319 that is configured to accommodate the central shaft 12640 ofthe pulley unit 12610 when the firing member 13310 is in itsproximal-most starting position within the firing member parking area10140 in the proximal end 10112 of the elongate channel 10110.

As shown in FIGS. 100-102 , the firing drive system 13000 furthercomprises an upper flexible chain drive assembly 13400 that is operablycoupled to the top portion 13315 of the firing member 13310 and a lowerflexible chain drive assembly 13500 that is operably coupled to thebottom portion 13313 of the firing member 13310. In at least oneembodiment, the upper flexible chain drive assembly 13400 comprises anupper series 13410 of upper chain link features 13420 that are looselycoupled together by an upper flexible coupler member 13402 that isattached to the top portion 13315 of the firing member 13310. In atleast one example, each upper chain link feature 13420 comprises anupper ball or sphere 13422 that has an upper hollow passage 13424therein that is configured to permit the upper flexible coupler member13402 to pass therethrough. As can be seen in FIG. 100 , the upperflexible chain drive assembly 13400 further comprises an uppercompression assembly 13430 for compressing the upper balls 13422 in theupper series 13410 together. In one arrangement, the upper compressionassembly 13430 comprises a hollow flexible compression tube 13432 thatis received on the upper flexible coupler member 13402. An upper ferrule13440 is crimped onto the upper flexible coupler member 13402 and anupper compression spring 13442 is journaled between the upper ferrule13440 and the upper flexible compression tube 13432 to distally bias theupper flexible compression tube 13432 into contact with theproximal-most upper ball 13422P in the upper series 13410 of upper chainlink features 13420.

Similarly, in at least one embodiment, the lower flexible chain driveassembly 13500 comprises a lower series 13510 of lower chain linkfeatures 13520 that are loosely coupled together by a lower flexiblecoupler member 13502 that is attached to the bottom portion 13313 of thefiring member 13310. In at least one example, each lower chain linkfeature 13520 comprises a lower ball or sphere 13522 that has a lowerhollow passage 13524 therein that is configured to permit the lowerflexible coupler member 13502 to pass therethrough. The lower flexiblechain drive assembly 13500 further comprises an upper compressionassembly 13530 for compressing the lower balls 13522 in the lower series13510 together. In one arrangement, the lower compression assembly 13530comprises a hollow flexible compression tube 13532 that is received onthe lower flexible coupler member 13502. A lower ferrule 13540 iscrimped onto the lower flexible coupler member 13502 and a lowercompression spring 13542 is journaled between the lower ferrule 13540and the lower flexible compression tube 13532 to distally bias the lowerflexible compression tube 13532 into contact with the proximal-mostlower ball 13522P in the lower series 13510 of lower chain link features13520.

Now turning to FIG. 104 , in at least one arrangement, the firing drivesystem 13000 further comprises rotary drive screw 13700 that isconfigured to drivingly interface with the upper series 13410 of upperchain link features 13420 and the lower series 13510 of lower chain linkfeatures 13520. As can be seen in FIG. 104 , in the illustratedarrangement, the rotary drive screw 13700 is rotatably supported in themounting bushing 10150 that is attached to the proximal end 10112 of theelongate channel 10110. For example, the rotary drive screw 13700comprises a body portion 13702 that has a central axle 13704 protrudingtherefrom that is rotatably mounted in a mounting hole 10152 in themounting bushing 10150. Such arrangement permits the rotary drive screw13700 to rotate about the shaft axis SA.

In the illustrated example, the rotary drive screw 13700 is driven by arotary drive system 13600 that comprises a proximal rotary drive shaft13610 that is rotatably supported within an axial passage 12225 withinthe proximal joint member 12210. As can be seen in FIG. 105 , theproximal rotary drive shaft 13610 comprises a proximal end 13612 and adistal end 13614. The proximal end 13612 may interface with a gearbox/motor arrangement 9050 or other source of rotary motion housed inthe housing 9020 of the surgical instrument 9010. Such source of rotarymotion causes the proximal rotary drive shaft 13610 to rotate about theshaft axis SA within the axial passage 12225 in the proximal jointmember 12210. See FIG. 104 . As can be seen in FIG. 105 , the distal end13614 of the proximal rotary drive shaft 13610 is movably coupled to afirst drive shaft segment 13620. In the illustrated example, the firstdrive shaft segment 13620 resembles a “dog bone” with a first sphericalproximal end 13622 and a first spherical distal end 13624. See FIG. 106. The first spherical proximal end 13622 is movably pinned within afirst distal socket 13616 formed in the distal end 13614 of the proximalrotary drive shaft 13610 by a first proximal pin 13618. The firstproximal pin 13618 extends through an arcuate transverse slot 13623 inthe first spherical proximal end 13622. Such arrangement permits thefirst spherical proximal end 13622 to move in multiple directions withinthe first distal socket 13616 while remaining attached thereto. Thefirst spherical distal end 13624 is received within a first proximalsocket 13632 in a central bearing housing 13630 that is mounted withinthe central joint member 12230. The first spherical distal end 13624 ismovably pinned within the first proximal socket 13632 by a first distalpin 13634. The first distal pin 13634 extends through an arcuatetransverse slot 13625 in the first spherical distal end 13624. Sucharrangement permits the first spherical distal end 13624 to move inmultiple directions within the first proximal socket 13632 whileremaining attached to the central bearing housing 13630.

As can be seen in FIG. 105 , the rotary drive system 13600 furthercomprises a second drive shaft segment 13640 that resembles the firstdrive shaft segment 13620 and includes a second spherical proximal end13642 and a second spherical distal end 13644. The second sphericalproximal end 13642 is movably pinned within a second distal socket 13636that is formed in the central bearing housing 13630 by a second proximalpin 13637. The second proximal pin 13637 extends through an arcuatetransverse slot 13643 in the second spherical proximal end 13642. Sucharrangement permits the second spherical proximal end 13642 to move inmultiple directions within the second distal socket 13636 whileremaining attached thereto. The second spherical distal end 13644 isreceived within a second proximal socket 13706 in the rotary drive screw13700 and is movably pinned within the second proximal socket 13706 by asecond distal pin 13647. The second distal pin 13647 extends through atransverse slot 13646 in the second spherical distal end 13644. Sucharrangement permits the second spherical distal end 13644 to move inmultiple directions relative to the rotary drive screw 13700.

The double joint rotary drive maintains a linear velocity output byusing the angle constraint of the joint members of the articulationjoint. This universal rotary joint arrangement on its own may have asinusoidal output based on the angle of the joint. If the angles areequal and the phases are aligned correctly, the sine output of the firstuniversal joint will be canceled out by the second universal joint,producing a linear rotational velocity. This is an advantage to puttinga constraint in the rotary drive because it decreases the complexity ofthe components and prevents the need to remove material from thecomponents to attain the requisite clearance. Thus, the components ofthis embodiment are more robust and stronger than prior arrangements.Further, the constant velocity of the rotary drive system will allow forsmoother firing and reduced wear that may be otherwise caused byvibration.

Returning to FIG. 102 , the rotary drive screw 13700 comprises helicalgrooves or drive features 13708 formed on a circumference thereof thatare configured to engage and drive the upper balls or spheres 13422 inthe upper series 13410 of upper chain link features 13420 and the lowerballs or spheres 13522 in the lower series 13510 of lower chain linkfeatures 13520. Thus, to drive the firing member 13310 from a startingposition in the surgical end effector 10000 to an ending position withinthe end effector, the rotary drive system 13600 is actuated to apply arotary drive motion to the rotary drive screw 13700. As the rotary drivescrew 13700 rotates in the first rotary direction, the helical drivefeatures 13708 engage the upper balls or spheres 13422 in the upperseries 13410 of upper chain link features 13420 and the lower balls orspheres 13522 in the lower series 13510 of lower chain link features13520 and drive the upper flexible chain drive assembly 13400 and thelower flexible chain drive assembly 13500 distally. As each upper ball13422 and lower ball 13522 engage the rotary drive screw 13700, theupper balls 13422 in the upper series 13410 that are distal to therotary drive screw 13700 (and the articulation joint 12200) and thelower balls 13522 in the lower series 13510 that are distal to therotary drive screw 13700 (and the articulation joint 12200) are placedunder compression to apply balanced axial drive forces to the firingmember 13310. When the upper flexible chain drive assembly 13400 and theflexible lower chain drive assembly 13500 are in compression, they areconstrained by the slots in the anvil 10210 and the elongate channel10110, respectively. Such arrangement ensures that, when the upperflexible chain drive assembly 13400 and lower flexible chain driveassembly 13500 are compressed, they do not buckle.

This arrangement enables two degrees of articulation freedom for a fewreasons. For example, the upper flexible chain drive assembly 13400 andlower flexible chain drive assembly 13500 can bend freely both in thepitch and yaw axes. Thus, the upper flexible chain drive assembly 13400and lower flexible chain drive assembly 13500 can assume a variety ofconfigurations that can accommodate various articulated positions thatare attainable with the articulation joint 12200. Once the firing member13310 has traveled through the surgical end effector 10000 distally toan ending position therein, the rotary drive system 13600 is actuated toapply a second rotary drive motion to the rotary drive screw 13700 tocause the rotary drive screw 13700 to rotate about the shaft axis in asecond rotary direction. As the rotary drive screw 13700 rotates in thesecond rotary direction, the upper flexible chain drive assembly 13400and the lower flexible chain drive assembly 13500 serve to retract thefiring member 13310 in the proximal direction back to the startingposition. As the upper flexible chain drive assembly 13400 and the lowerflexible chain drive assembly 13500 retract the firing member 13310proximally, a portion of the upper flexible chain drive assembly 13400and the lower flexible chain drive assembly 13500 traverse back throughthe articulation joint 12200 and into the elongate shaft. Sucharrangement allows the firing member 13310 to translate a long distance,without increasing the length of the end effector joint. Additionally,because the rotary drive screw 13700 drivingly engages the upperflexible chain drive assembly 13400 and the lower flexible chain driveassembly 13500 at a location that is distal to the articulation joint12200, the high compressive loads are contained within the surgical endeffector 10000 and do not create a moment on the articulation joint12200. This arrangement may greatly reduce the strength requirements ofthe articulation joint. See FIG. 104 .

In at least one arrangement, the surgical instrument 9010 may furthercomprise a cable tensioning system 13800 that is configured to maintaina desired amount of tension on the upper flexible chain drive assembly13400 and the lower flexible chain drive assembly 13500 as they bendthrough the articulation joint 12200. Keeping the upper flexible chaindrive assembly 13400 and the lower flexible chain drive assembly 13500under a desired amount of tension as they traverse through thearticulation joint 12200 may prevent slack from forming in thoseflexible chain drive assemblies 13400, 13500 which might otherwise causethem to undesirably bunch up in the articulation joint 12200. FIGS. 111and 112 illustrate one form of cable tensioning system 13800 whichcomprises constant force spring arrangements 13810 and 13820. Suchsolution has the benefit of not requiring length conservation of theflexible chain drive assemblies 13400, 13500.

Another cable management system 13800′ is illustrated in FIGS. 113 and114 . In this arrangement, the proximal ends of the flexible chain driveassemblies 13400, 13500 are coupled together by a coupler member 13842that is journaled around a cable management pulley 13840 that isconfigured to translate with the firing member 13310. When the firingmember 13310 is distally advanced during the firing stroke, the cablemanagement pulley 13840 also translates distally maintaining tension inthe flexible chain drive assemblies 13400, 13500. During articulation, alength of one of the flexible chain drive assemblies 13400, 13500 wouldincrease, while the other would decrease. Such arrangement serves tominimize the lengths of the flexible chain drive assemblies 13400, 13500required to fully actuate and articulate the surgical end effector10000.

One method of using the surgical instrument 9010 may involve the use ofthe surgical instrument to cut and staple target tissue within a patientusing laparoscopic techniques. For example, one or more trocars may havebeen placed through the abdominal wall of a patient to provide access toa target tissue within the patient. The surgical end effector 10000 maybe inserted through one trocar and one or more cameras or other surgicalinstruments may be inserted through the other trocar(s). To enable thesurgical end effector 10000 to pass through the trocar cannula, thesurgical end effector 10000 is positioned in an unarticulatedorientation (FIG. 63 ) and the jaws 10100 and 10200 must be closed. Toretain the jaws 10100 in the closed position for insertion purposes, forexample, the cable control system 9030 is actuated to pull the firstcable 12510 and the fourth cable 12540 simultaneously which causes thepulley unit 12610 to rotate and cause the closure cams 10626, 10636 tocontact the anvil closure arms 10234 to pivot the anvil 10210 into theclosed position. See FIG. 97 . The cable control system 9030 isdeactivated to retain the anvil 10210 in the closed position. Once thesurgical end effector 10000 has passed into the abdomen through thetrocar, the cable control system 9030 is activated to rotate the pulleyunit 12610 in an opposite direction to the position shown in FIG. 96 topermit the anvil 10210 to be biased open by the anvil springs 10240.

Once inside the abdomen and before engaging the target tissue, thesurgeon may need to articulate the surgical end effector 10000 into anadvantageous position. The cable control system 9030 may then beactuated to articulate the surgical end effector 10000 in one or moreplanes relative to a portion of the elongate shaft assembly 12000 thatis received within the cannula of the trocar. Once the surgeon hasoriented the surgical end effector 10000 in a desirable position, thecable control system 9030 is deactivated to retain the surgical endeffector 10000 in the articulated orientation. Thereafter, the surgeonmay activate the cable control system 9030 in the above-described mannerto cause the anvil 10210 to rapidly close to grasp the tissue betweenthe anvil 10210 and the surgical staple cartridge 10300. This processmay be repeated as necessary until the target tissue has be properlypositioned between the anvil 10210 and the surgical staple cartridge10300.

Once the target tissue has been positioned between the anvil 10210 andthe surgical staple cartridge 10300, the surgeon may activate the cablecontrol system 9030 to close the anvil 10210 to clamp the target tissuein position. Thereafter, the firing process may be commenced byactivating the rotary drive system 13600 to drive the firing member13310 distally from the starting position. As the firing member 13310moves distally, the firing member 13310 contacts a sled that issupported in the surgical staple cartridge 10300 and also drives thesled distally through the staple cartridge body. The sled seriallydrives rows of drivers supported in the staple cartridge toward theclamped target tissue. Each driver has supported thereon one or moresurgical staples or fasteners which are then driven through the targettissue and into forming contact with the underside of the anvil 10210.As the firing member 13310 moves distally, the tissue cutting edge 13318thereon cuts through the stapled tissue.

After the firing member 13310 has been driven distally to the endingposition within the surgical end effector 10000, the rotary drive system13600 is reversed which causes the firing member 13310 to retractproximally back to the starting position. Once the firing member 13310has returned to the starting position, the cable control system 9030 maybe activated to rotate the pulley unit 12610 back to an open positionwherein the anvil springs 10240 can pivot the anvil 10210 to the openposition to enable the surgeon to release the stapled tissue from thesurgical end effector 10000. Once the stapled tissue has been released,the surgical end effector 10000 may be withdrawn out of the patientthrough the trocar cannula. To do so, the surgeon must first actuate thecable control system 9030 to return the surgical end effector 10000 toan unarticulated position and actuate the cable control system 9030 topivot the anvil 10210 to the closed position. Thereafter, the surgicalend effector 10000 may be withdrawn through the trocar cannula.

In previous endocutter arrangements, the firing member is pushed by aflexible beam. In such arrangements, the articulation joint mustredirect the linear motion of the flexible beam as it enters thearticulation joint back to that linear motion as it exits thearticulation joint and enters the end effector. Because of the highloads required to push the flexible beam and the firing member, theflexible beam commonly experiences high amounts of friction as it exitsthe articulation joint and is linearly redirected into the end effector.This added amount of friction increases the amount of driving forcesthat are required to drive the firing member from the starting to endingposition within the end effector while the end effector is articulated.Further, as the flexible beam traverses the articulation joint, it mayapply de-articulation motions to the articulation joint components.Thus, the articulation joint components must be sufficiently robust soas to resist such de-articulation motions.

Other forms of surgical endocutters employ rotary forces to drive thefiring member through the end effector. Such arrangements commonlyemploy a rotary drive screw that is housed within the channel thatsupports the staple cartridge. During use, the sled and tissue placelarge moments on the firing member which decrease the efficiency of thesystem and ultimately require higher rotary forces to actuate the firingmember. It is difficult to move the rotary drive screw closer to thecenter of such forces because of the cartridge and the location of thetissue. It is also difficult to package a screw on top and bottom of thefiring member without increasing the overall diameter of the surgicalend effector. The various embodiments discussed above may address manyif not all of these issues and challenges.

Example 1—A surgical instrument comprising a surgical end effector thatincludes a firing member that is supported for axial travel within thesurgical end effector. An upper chain-drive assembly operably interfaceswith a top portion of the firing member and a lower chain-drive assemblyoperably interfaces with a bottom portion of the firing member. A drivemember operably interfaces with the upper chain-drive assembly and thelower chain-drive assembly to cause the upper chain-drive assembly andthe lower chain-drive assembly to apply axial drive motions to thefiring member to move the firing member between a starting position andan ending position within the surgical end effector.

Example 2—The surgical instrument of Example 1, wherein the upperchain-drive assembly comprises a plurality of upper chain link featuresthat are movably interconnected by an upper flexible member and whereinthe lower chain-drive assembly comprises a plurality of lower chain linkfeatures that are movably interconnected by a lower flexible member.

Example 3—The surgical instrument of Example 2, further comprising anupper tensioner that is attached to a proximal end of the upper flexiblemember to maintain variable tension in the upper chain-drive assemblyand a lower tensioner that is attached to a proximal end of the lowerflexible member to maintain variable tension in the lower chain-driveassembly.

Example 4—The surgical instrument of Examples 2 or 3, wherein each upperchain-link feature comprises an upper sphere and wherein each lowerchain-link feature comprises a lower sphere.

Example 5—The surgical instrument of Examples 1, 2, 3 or 4, furthercomprising an elongate shaft that is coupled to the surgical endeffector by an articulation joint that is configured to facilitateselective articulation of the surgical end effector relative to theelongate shaft. The drive member operably interfaces with the upperchain-drive assembly at an upper location and the drive member operablyinterfaces with the lower chain-drive assembly at a lower location. Theupper location and the lower location are distal to the articulationjoint.

Example 6—The surgical instrument of Example 5, wherein the articulationjoint comprises a multi-axis articulation joint.

Example 7—The surgical instrument of Examples 1, 2, 3, 4 or 6, wherein aproximal upper portion of the upper chain-drive assembly that isproximal to the drive member is loosely coupled together and an upperdistal portion of the upper chain-drive assembly that is distal to thedrive member is compressed into a substantially rigid upper state thatis configured to apply an upper axial drive motion to the firing member.A lower proximal portion of the lower chain-drive assembly that isproximal to the drive member is loosely coupled together and a lowerdistal portion of the lower chain-drive assembly that is distal to thedrive member is compressed into a substantially rigid lower state thatis configured to apply a lower axial drive motion to the firing member.

Example 8—The surgical instrument of Examples 1, 2, 3, 4, 5, 6 or 7,wherein the upper chain-drive assembly comprises an upper proximal endand an upper distal end that operably interfaces with the top portion ofthe firing member. The lower chain-drive assembly comprises a lowerproximal end and a lower distal end that operably interfaces with thebottom portion of the firing member. The upper proximal end is coupledto the lower proximal end by a coupler member that is supported inoperable engagement with a proximal support member that facilitatesmovement of the coupler member and the upper chain-drive assembly andthe lower chain drive assembly. The proximal support member isconfigured to translate axially as the upper chain-drive assembly andthe lower chain-drive assembly translate axially.

Example 9—The surgical instrument of Examples 5 or 6, wherein the drivemember is located between the upper chain-drive assembly and the lowerchain-drive assembly and is supported in a position that is distal tothe articulation joint.

Example 10—A surgical instrument comprising an elongate shaft that has asurgical end effector coupled thereto by an articulation joint that isconfigured to facilitate selective articulation of the surgical endeffector relative to the elongate shaft. The surgical end effectorcomprises a first jaw and a second jaw that is configured to moverelative to the first jaw between an open position and a closedposition. A firing member is supported for axial travel within thesurgical end effector between a starting position and an endingposition. The surgical instrument further comprises an upper chain-driveassembly that is attached to a top portion of the firing member and alower chain-drive assembly that is attached to a bottom portion of thefiring member. A rotary drive member operably interfaces with the upperchain-drive assembly at an upper location and with the lower chain-driveassembly at a lower location. The upper location and the lower locationare distal to the articulation joint. The rotary drive member causes theupper chain-drive assembly and the lower chain-drive assembly to applyaxial drive motions to the firing member to move the firing memberbetween the starting position and the ending position.

Example 11—The surgical instrument of Example 10, wherein the upperchain-drive assembly comprises a plurality of upper chain link featuresthat are movably interconnected by an upper flexible member and thelower chain-drive assembly comprises a plurality of lower chain linkfeatures that are movably interconnected by a lower flexible member.

Example 12—The surgical instrument of Example 11 further comprising anupper tensioner that is attached to a proximal end of the upper flexiblemember to maintain variable tension in the upper chain-drive assemblyand a lower tensioner that is attached to a proximal end of the lowerflexible member to maintain variable tension in the lower chain-driveassembly.

Example 13—The surgical instrument of Examples 10, 11 or 12, whereineach upper chain-link feature comprises an upper sphere and each lowerchain-link feature comprises a lower sphere.

Example 14—The surgical instrument of Examples 10, 11, 12 or 13, whereinthe first jaw comprises a bottom passage that is configured to slidablyaccommodate the bottom portion of the firing member and a distal portionof the lower chain-drive assembly and the second jaw comprises a toppassage that is configured to slidably accommodate the top portion ofthe firing member and a distal portion of the upper chain-drive assemblywhen the firing member is moved between the starting position and theending position.

Example 15—The surgical instrument of Example 14, wherein the bottompassage is sized and shaped relative to each lower sphere in the distalportion of the lower chain-drive assembly to prevent the distal portionof the lower chain-drive assembly from buckling as the firing member isdriven from the starting position to the ending position. The toppassage is sized and shaped relative to each upper sphere in the distalportion of the upper chain-drive assembly to prevent the distal portionof the upper chain-drive assembly from buckling as the firing member isdriven from the starting position to the ending position.

Example 16—The surgical instrument of Examples 14 or 15, wherein thebottom passage comprises a bottom keyhole shape and the top passagecomprises a top keyhole shape.

Example 17—The surgical instrument of Examples 10, 11, 12, 13, 14, 15 or16, wherein the firing member is movable from a position distal to thestarting position to the starting position without actuating the rotarydrive member by applying an axial bailout motion to each of the upperchain-drive assembly and the lower chain-drive assembly.

Example 18—A surgical instrument, comprising an elongate shaft that hasa surgical end effector coupled thereto by an articulation joint that isconfigured to facilitate selective articulation of the surgical endeffector relative to the elongate shaft. The surgical end effectorcomprises a firing member that is supported for axial travel within thesurgical end effector between a starting position and an endingposition. An upper loosely-linked chain-drive assembly is supported bythe elongate shaft and traverses the articulation joint to operablyinterface with a top portion of the firing member. A lowerloosely-linked chain-drive assembly is supported by the elongate shaftand traverses the articulation joint to operably interface with a bottomportion of the firing member. The surgical instrument further comprisesmeans for converting an upper portion of the upper loosely-linkedchain-drive assembly that is distal to the articulation joint into arigid drive member that is configured to apply axial drive motions tothe firing member to drive the firing member between the startingposition and the ending position.

Example 19—The surgical instrument of Example 18, wherein the upperloosely-linked chain-drive assembly comprises a plurality of upper chainlink features that are movably interconnected by an upper flexiblemember and the lower loosely-linked chain-drive assembly comprises aplurality of lower chain link features that are movably interconnectedby a lower flexible member.

Example 20—The surgical instrument of Example 19, wherein each upperchain-link feature comprises an upper sphere and wherein each lowerchain-link feature comprises a lower sphere.

As used in any aspect herein, the term “control circuit” may refer to,for example, hardwired circuitry, programmable circuitry (e.g., acomputer processor including one or more individual instructionprocessing cores, processing unit, processor, microcontroller,microcontroller unit, controller, digital signal processor (DSP),programmable logic device (PLD), programmable logic array (PLA), orfield programmable gate array (FPGA)), state machine circuitry, firmwarethat stores instructions executed by programmable circuitry, and anycombination thereof. The control circuit may, collectively orindividually, be embodied as circuitry that forms part of a largersystem, for example, an integrated circuit (IC), an application-specificintegrated circuit (ASIC), a system on-chip (SoC), desktop computers,laptop computers, tablet computers, servers, smart phones, etc.Accordingly, as used herein “control circuit” includes, but is notlimited to, electrical circuitry having at least one discrete electricalcircuit, electrical circuitry having at least one integrated circuit,electrical circuitry having at least one application specific integratedcircuit, electrical circuitry forming a general purpose computing deviceconfigured by a computer program (e.g., a general purpose computerconfigured by a computer program which at least partially carries outprocesses and/or devices described herein, or a microprocessorconfigured by a computer program which at least partially carries outprocesses and/or devices described herein), electrical circuitry forminga memory device (e.g., forms of random access memory), and/or electricalcircuitry forming a communications device (e.g., a modem, communicationsswitch, or optical-electrical equipment). Those having skill in the artwill recognize that the subject matter described herein may beimplemented in an analog or digital fashion or some combination thereof.

While several forms have been illustrated and described, it is not theintention of Applicant to restrict or limit the scope of the appendedclaims to such detail. Numerous modifications, variations, changes,substitutions, combinations, and equivalents to those forms may beimplemented and will occur to those skilled in the art without departingfrom the scope of the present disclosure. Moreover, the structure ofeach element associated with the described forms can be alternativelydescribed as a means for providing the function performed by theelement. Also, where materials are disclosed for certain components,other materials may be used. It is therefore to be understood that theforegoing description and the appended claims are intended to cover allsuch modifications, combinations, and variations as falling within thescope of the disclosed forms. The appended claims are intended to coverall such modifications, variations, changes, substitutions,modifications, and equivalents.

One or more components may be referred to herein as “configured to,”“configurable to,” “operable/operative to,” “adapted/adaptable,” “ableto,” “conformable/conformed to,” etc. Those skilled in the art willrecognize that “configured to” can generally encompass active-statecomponents and/or inactive-state components and/or standby-statecomponents, unless context requires otherwise.

Those skilled in the art will recognize that, in general, terms usedherein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to claims containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations.

In addition, even if a specific number of an introduced claim recitationis explicitly recited, those skilled in the art will recognize that suchrecitation should typically be interpreted to mean at least the recitednumber (e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that typically a disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms unless context dictates otherwise. For example, the phrase “Aor B” will be typically understood to include the possibilities of “A”or “B” or “A and B.”

With respect to the appended claims, those skilled in the art willappreciate that recited operations therein may generally be performed inany order. Also, although various operational flow diagrams arepresented in a sequence(s), it should be understood that the variousoperations may be performed in other orders than those which areillustrated, or may be performed concurrently. Examples of suchalternate orderings may include overlapping, interleaved, interrupted,reordered, incremental, preparatory, supplemental, simultaneous,reverse, or other variant orderings, unless context dictates otherwise.Furthermore, terms like “responsive to,” “related to,” or otherpast-tense adjectives are generally not intended to exclude suchvariants, unless context dictates otherwise.

It is worthy to note that any reference to “one aspect,” “an aspect,”“an exemplification,” “one exemplification,” and the like means that aparticular feature, structure, or characteristic described in connectionwith the aspect is included in at least one aspect. Thus, appearances ofthe phrases “in one aspect,” “in an aspect,” “in an exemplification,”and “in one exemplification” in various places throughout thespecification are not necessarily all referring to the same aspect.Furthermore, the particular features, structures or characteristics maybe combined in any suitable manner in one or more aspects.

Any patent application, patent, non-patent publication, or otherdisclosure material referred to in this specification and/or listed inany Application Data Sheet is incorporated by reference herein, to theextent that the incorporated materials is not inconsistent herewith. Assuch, and to the extent necessary, the disclosure as explicitly setforth herein supersedes any conflicting material incorporated herein byreference. Any material, or portion thereof, that is said to beincorporated by reference herein, but which conflicts with existingdefinitions, statements, or other disclosure material set forth hereinwill only be incorporated to the extent that no conflict arises betweenthat incorporated material and the existing disclosure material.

In summary, numerous benefits have been described which result fromemploying the concepts described herein. The foregoing description ofthe one or more forms has been presented for purposes of illustrationand description. It is not intended to be exhaustive or limiting to theprecise form disclosed. Modifications or variations are possible inlight of the above teachings. The one or more forms were chosen anddescribed in order to illustrate principles and practical application tothereby enable one of ordinary skill in the art to utilize the variousforms and with various modifications as are suited to the particular usecontemplated. It is intended that the claims submitted herewith definethe overall scope.

The surgical instrument systems described herein have been described inconnection with the deployment and deformation of staples; however, theembodiments described herein are not so limited. Various embodiments areenvisioned which deploy fasteners other than staples, such as clamps ortacks, for example. Moreover, various embodiments are envisioned whichutilize any suitable means for sealing tissue. For instance, an endeffector in accordance with various embodiments can comprise electrodesconfigured to heat and seal the tissue. Also, for instance, an endeffector in accordance with certain embodiments can apply vibrationalenergy to seal the tissue.

Many of the surgical instrument systems described herein are motivatedby an electric motor; however, the surgical instrument systems describedherein can be motivated in any suitable manner. In various instances,the surgical instrument systems described herein can be motivated by amanually-operated trigger, for example. In certain instances, the motorsdisclosed herein may comprise a portion or portions of a roboticallycontrolled system. Moreover, any of the end effectors and/or toolassemblies disclosed herein can be utilized with a robotic surgicalinstrument system. U.S. patent application Ser. No. 13/118,241, entitledSURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENTARRANGEMENTS, now U.S. Pat. No. 9,072,535, for example, disclosesseveral examples of a robotic surgical instrument system in greaterdetail.

The entire disclosures of:

U.S. Pat. No. 5,403,312, entitled ELECTROSURGICAL HEMOSTATIC DEVICE,which issued on Apr. 4, 1995;

U.S. Pat. No. 7,000,818, entitled SURGICAL STAPLING INSTRUMENT HAVINGSEPARATE DISTINCT CLOSING AND FIRING SYSTEMS, which issued on Feb. 21,2006;

U.S. Pat. No. 7,422,139, entitled MOTOR-DRIVEN SURGICAL CUTTING ANDFASTENING INSTRUMENT WITH TACTILE POSITION FEEDBACK, which issued onSep. 9, 2008;

U.S. Pat. No. 7,464,849, entitled ELECTRO-MECHANICAL SURGICAL INSTRUMENTWITH CLOSURE SYSTEM AND ANVIL ALIGNMENT COMPONENTS, which issued on Dec.16, 2008;

U.S. Pat. No. 7,670,334, entitled SURGICAL INSTRUMENT HAVING ANARTICULATING END EFFECTOR, which issued on Mar. 2, 2010;

U.S. Pat. No. 7,753,245, entitled SURGICAL STAPLING INSTRUMENTS, whichissued on Jul. 13, 2010;

U.S. Pat. No. 8,393,514, entitled SELECTIVELY ORIENTABLE IMPLANTABLEFASTENER CARTRIDGE, which issued on Mar. 12, 2013;

U.S. patent application Ser. No. 11/343,803, entitled SURGICALINSTRUMENT HAVING RECORDING CAPABILITIES, now U.S. Pat. No. 7,845,537;

U.S. patent application Ser. No. 12/031,573, entitled SURGICAL CUTTINGAND FASTENING INSTRUMENT HAVING RF ELECTRODES, filed Feb. 14, 2008;

U.S. patent application Ser. No. 12/031,873, entitled END EFFECTORS FORA SURGICAL CUTTING AND STAPLING INSTRUMENT, filed Feb. 15, 2008, nowU.S. Pat. No. 7,980,443;

U.S. patent application Ser. No. 12/235,782, entitled MOTOR-DRIVENSURGICAL CUTTING INSTRUMENT, now U.S. Pat. No. 8,210,411;

U.S. patent application Ser. No. 12/235,972, entitled MOTORIZED SURGICALINSTRUMENT, now U.S. Pat. No. 9,050,083;

U.S. patent application Ser. No. 12/249,117, entitled POWERED SURGICALCUTTING AND STAPLING APPARATUS WITH MANUALLY RETRACTABLE FIRING SYSTEM,now U.S. Pat. No. 8,608,045;

U.S. patent application Ser. No. 12/647,100, entitled MOTOR-DRIVENSURGICAL CUTTING INSTRUMENT WITH ELECTRIC ACTUATOR DIRECTIONAL CONTROLASSEMBLY, filed Dec. 24, 2009, now U.S. Pat. No. 8,220,688;

U.S. patent application Ser. No. 12/893,461, entitled STAPLE CARTRIDGE,filed Sep. 29, 2012, now U.S. Pat. No. 8,733,613;

U.S. patent application Ser. No. 13/036,647, entitled SURGICAL STAPLINGINSTRUMENT, filed Feb. 28, 2011, now U.S. Pat. No. 8,561,870;

U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLINGINSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat.No. 9,072,535;

U.S. patent application Ser. No. 13/524,049, entitled ARTICULATABLESURGICAL INSTRUMENT COMPRISING A FIRING DRIVE, filed on Jun. 15, 2012,now U.S. Pat. No. 9,101,358;

U.S. patent application Ser. No. 13/800,025, entitled STAPLE CARTRIDGETISSUE THICKNESS SENSOR SYSTEM, filed on Mar. 13, 2013, now U.S. Pat.No. 9,345,481;

U.S. patent application Ser. No. 13/800,067, entitled STAPLE CARTRIDGETISSUE THICKNESS SENSOR SYSTEM, filed on Mar. 13, 2013, now U.S. PatentApplication Publication No. 2014/0263552;

U. S. Patent Application Publication No. 2007/0175955, entitled SURGICALCUTTING AND FASTENING INSTRUMENT WITH CLOSURE TRIGGER LOCKING MECHANISM,filed Jan. 31, 2006; and

U. S. Patent Application Publication No. 2010/0264194, entitled SURGICALSTAPLING INSTRUMENT WITH AN ARTICULATABLE END EFFECTOR, filed Apr. 22,2010, now U.S. Pat. No. 8,308,040, are hereby incorporated by referenceherein.

Although various devices have been described herein in connection withcertain embodiments, modifications and variations to those embodimentsmay be implemented. Particular features, structures, or characteristicsmay be combined in any suitable manner in one or more embodiments. Thus,the particular features, structures, or characteristics illustrated ordescribed in connection with one embodiment may be combined in whole orin part, with the features, structures or characteristics of one or moreother embodiments without limitation. Also, where materials aredisclosed for certain components, other materials may be used.Furthermore, according to various embodiments, a single component may bereplaced by multiple components, and multiple components may be replacedby a single component, to perform a given function or functions. Theforegoing description and following claims are intended to cover allsuch modification and variations.

The devices disclosed herein can be designed to be disposed of after asingle use, or they can be designed to be used multiple times. In eithercase, however, a device can be reconditioned for reuse after at leastone use. Reconditioning can include any combination of the stepsincluding, but not limited to, the disassembly of the device, followedby cleaning or replacement of particular pieces of the device, andsubsequent reassembly of the device. In particular, a reconditioningfacility and/or surgical team can disassemble a device and, aftercleaning and/or replacing particular parts of the device, the device canbe reassembled for subsequent use. Those skilled in the art willappreciate that reconditioning of a device can utilize a variety oftechniques for disassembly, cleaning/replacement, and reassembly. Use ofsuch techniques, and the resulting reconditioned device, are all withinthe scope of the present application.

The devices disclosed herein may be processed before surgery. First, anew or used instrument may be obtained and, when necessary, cleaned. Theinstrument may then be sterilized. In one sterilization technique, theinstrument is placed in a closed and sealed container, such as a plasticor TYVEK bag. The container and instrument may then be placed in a fieldof radiation that can penetrate the container, such as gamma radiation,x-rays, and/or high-energy electrons. The radiation may kill bacteria onthe instrument and in the container. The sterilized instrument may thenbe stored in the sterile container. The sealed container may keep theinstrument sterile until it is opened in a medical facility. A devicemay also be sterilized using any other technique known in the art,including but not limited to beta radiation, gamma radiation, ethyleneoxide, plasma peroxide, and/or steam.

While this invention has been described as having exemplary designs, thepresent invention may be further modified within the spirit and scope ofthe disclosure. This application is therefore intended to cover anyvariations, uses, or adaptations of the invention using its generalprinciples.

What is claimed is:
 1. A surgical instrument, comprising: a surgical endeffector comprising a firing member supported for axial travel withinsaid surgical end effector; an upper chain-drive assembly operablyinterfacing with a top portion of said firing member and having an upperproximal end and an upper distal end; a lower chain-drive assemblyoperably interfacing with a bottom portion of said firing member andhaving a lower proximal end and a lower distal end; a drive member,wherein said drive member operably interfaces with said upperchain-drive assembly and said lower chain-drive assembly to cause saidupper chain-drive assembly and said lower chain-drive assembly to applyaxial drive motions to said firing member to move said firing memberbetween a starting position and an ending position within said surgicalend effector; and a coupler, wherein said upper proximal end is coupledto said lower proximal end by said coupler, wherein said coupler issupported in operable engagement with a proximal support thatfacilitates movement of said coupler and said upper chain-drive assemblyand said lower chain drive assembly, and wherein said proximal supportis configured to translate axially as said upper chain-drive assemblyand said lower chain-drive assembly translate axially.
 2. The surgicalinstrument of claim 1, wherein said upper chain-drive assembly comprisesa plurality of upper chain link features movably interconnected by anupper flexible member and wherein said lower chain-drive assemblycomprises a plurality of lower chain link features movablyinterconnected by a lower flexible member.
 3. The surgical instrument ofclaim 2, further comprising: an upper tensioner attached to a proximalend of said upper flexible member to maintain variable tension in saidupper chain-drive assembly; and a lower tensioner attached to a proximalend of said lower flexible member to maintain variable tension in saidlower chain-drive assembly.
 4. The surgical instrument of claim 2,wherein each said upper chain-link feature comprises an upper sphere andwherein each said lower chain-link feature comprises a lower sphere. 5.The surgical instrument of claim 1, further comprising an elongate shaftcoupled to said surgical end effector by an articulation joint, whereinsaid articulation joint is configured to facilitate selectivearticulation of said surgical end effector relative to said elongateshaft, wherein said drive member operably interfaces with said upperchain-drive assembly at an upper location, wherein said drive memberoperably interfaces with said lower chain-drive assembly at a lowerlocation, and wherein said upper location and said lower location aredistal to said articulation joint.
 6. The surgical instrument of claim5, wherein said articulation joint comprises a multi-axis articulationjoint.
 7. The surgical instrument of claim 5, wherein said drive memberis located between said upper chain-drive assembly and said lowerchain-drive assembly, and wherein said drive member is supported in aposition that is distal to said articulation joint.
 8. The surgicalinstrument of claim 1, wherein a proximal upper portion of said upperchain-drive assembly that is proximal to said drive member is looselycoupled together, wherein an upper distal portion of said upperchain-drive assembly that is distal to said drive member is compressedinto a substantially rigid upper state configured to apply an upper saidaxial drive motion to said firing member, wherein a lower proximalportion of said lower chain-drive assembly that is proximal to saiddrive member is loosely coupled together, wherein a lower distal portionof said lower chain-drive assembly that is distal to said drive memberis compressed into a substantially rigid lower state configured to applya lower said axial drive motion to said firing member.
 9. The surgicalinstrument of claim 1, wherein said upper distal end operably interfaceswith said top portion of said firing member, wherein said lower distalend operably interfaces with said bottom portion of said firing member.10. A surgical instrument, comprising: an elongate shaft; a surgical endeffector coupled to said elongate shaft by an articulation joint,wherein said articulation joint is configured to facilitate selectivearticulation of said surgical end effector relative to said elongateshaft, and wherein said surgical end effector comprises: a first jaw; asecond jaw, wherein said second jaw is configured to move relative tosaid first jaw between an open position and a closed position; and afiring member supported for axial travel within said surgical endeffector between a starting position and an ending position, and whereinsaid surgical instrument further comprises: an upper chain-driveassembly attached to a top portion of said firing member; a lowerchain-drive assembly attached to a bottom portion of said firing member;and a rotary drive member having a diameter, wherein said rotary drivemember operably interfaces with said upper chain-drive assembly at anupper location, wherein said rotary drive member operably interfaceswith said lower chain-drive assembly at a lower location, wherein saidupper location and said lower location are distal to said articulationjoint and are distanced from each other by at least the diameter suchthat said upper chain-drive assembly and said lower chain-drive assemblyare distanced by a gap, and wherein said rotary drive member causes saidupper chain-drive assembly and said lower chain-drive assembly to applyaxial drive motions to said firing member to move said firing memberbetween said starting position and said ending position.
 11. Thesurgical instrument of claim 10, wherein said upper chain-drive assemblycomprises a plurality of upper chain link features movablyinterconnected by an upper flexible member and wherein said lowerchain-drive assembly comprises a plurality of lower chain link featuresmovably interconnected by a lower flexible member.
 12. The surgicalinstrument of claim 11, further comprising: an upper tensioner attachedto a proximal end of said upper flexible member to maintain variabletension in said upper chain-drive assembly; and a lower tensionerattached to a proximal end of said lower flexible member to maintainvariable tension in said lower chain-drive assembly.
 13. The surgicalinstrument of claim 11, wherein each said upper chain-link featurecomprises an upper sphere and wherein each said lower chain-link featurecomprises a lower sphere.
 14. The surgical instrument of claim 13,wherein said first jaw comprises a bottom passage configured to slidablyaccommodate said bottom portion of said firing member and a distalportion of said lower chain-drive assembly, and wherein said second jawcomprises a top passage configured to slidably accommodate said topportion of said firing member and a distal portion of said upperchain-drive assembly when said firing member is moved between saidstarting position and said ending position.
 15. The surgical instrumentof claim 14, wherein said bottom passage is sized and shaped relative toeach said lower sphere in said distal portion of said lower chain-driveassembly to prevent said distal portion of said lower chain-driveassembly from buckling as said firing member is driven from saidstarting position to said ending position, and wherein said top passageis sized and shaped relative to each said upper sphere in said distalportion of said upper chain-drive assembly to prevent said distalportion of said upper chain-drive assembly from buckling as said firingmember is driven from said starting position to said ending position.16. The surgical instrument of claim 10, wherein said firing member ismovable from a position distal to said starting position to saidstarting position without actuating said rotary drive member by applyingan axial bailout motion to each of said upper chain-drive assembly andsaid lower chain-drive assembly.
 17. A surgical instrument, comprising:an elongate shaft; a surgical end effector coupled to said elongateshaft by an articulation joint, wherein said articulation joint isconfigured to facilitate selective articulation of said surgical endeffector relative to said elongate shaft, and wherein said surgical endeffector comprises a first jaw, a second jaw, and a firing membersupported for axial travel within each of said first and second jawsbetween a starting position and an ending position, wherein said firstand second jaws collectively define a gap; an upper loosely-linkedchain-drive assembly supported by said elongate shaft and traversingsaid articulation joint to operably interface with a top portion of saidfiring member; a lower loosely-linked chain-drive assembly supported bysaid elongate shaft and traversing said articulation joint to operablyinterface with a bottom portion of said firing member; and means forconverting an upper portion of said upper loosely-linked chain-driveassembly that is distal to said articulation joint into an upper rigiddrive member configured to travel within said first jaw and to applyaxial drive motions to said firing member to drive said firing memberbetween said starting position and said ending position, wherein aportion of said lower loosely-linked chain-drive assembly is configuredto convert into a lower rigid drive member that is configured totranslate within said second jaw to thus be distanced from said upperrigid drive member by at least the gap.
 18. The surgical instrument ofclaim 17, wherein said upper loosely-linked chain-drive assemblycomprises a plurality of upper chain link features movablyinterconnected by an upper flexible member, and wherein said lowerloosely-linked chain-drive assembly comprises a plurality of lower chainlink features movably interconnected by a lower flexible member.
 19. Thesurgical instrument of claim 18, wherein each said upper chain-linkfeature comprises an upper sphere and wherein each said lower chain-linkfeature comprises a lower sphere.
 20. A surgical instrument, comprising:a surgical end effector comprising a firing member configured to beactuated longitudinally; an upper chain-drive assembly coupled to a topportion of said firing member; a lower chain-drive assembly coupled to abottom portion of said firing member; and a rotary drive membercomprising a helical drive feature formed on a circumference thereof,wherein said helical drive feature operably interfaces with said upperchain-drive assembly and said lower chain-drive assembly on opposingends of said helical drive feature to thereby maintain a gap betweensaid upper and lower chain-drive assemblies and to cause said upperchain-drive assembly to apply an upper drive motion to said firingmember and said lower chain-drive assembly to apply a lower drive motionto said firing member to move said firing member between a startingposition and an ending position within said surgical end effector.
 21. Asurgical instrument, comprising: a surgical end effector comprising afiring member configured to be actuated longitudinally; an upperchain-drive assembly operably interfacing with a top portion of saidfiring member; a lower chain-drive assembly operably interfacing with abottom portion of said firing member, wherein said lower chain-driveassembly is permanently spaced from said upper chain-drive assembly andout of engagement therewith; and a drive member, wherein said drivemember operably interfaces with said upper chain-drive assembly and saidlower chain-drive assembly to cause said upper chain-drive assembly andsaid lower chain-drive assembly to apply axial drive motions to saidfiring member to move said firing member between a starting position andan ending position within said surgical end effector.